Codebase Scanner
Scan a folder, repository, npm/pypi package, or dependencies for malicious signatures.
Made with ❤️ by Jay Mathis

Usage
Usage: codebase-scanner [options] [command]
Scan a folder, repository, npm/pypi package, or dependencies for malicious signatures.
Options:
-V, --version output the version number
-f, --fix Fix flagged files by injecting a plain text header (local command only)
-a, --all Scan all files, ignoring default extension filters (applies to all scan commands)
-l, --limit <size> Set the file size limit in bytes (default: 1MB, applies to all scan commands)
-j, --json Output results in JSON format (applies to all scan commands)
-h, --help display help for command
Commands:
local [options] [folder] Scan a local folder (defaults to current directory)
npm [options] <package> Download and scan an npm package
pypi [options] <package> Download and scan a PyPI package
deps [options] <path> Scan dependencies specified in a directory (package.json/requirements.txt)
help [command] display help for command
Scan a repository in a Docker container
docker run -it --rm mathiscode/codebase-scanner:latest
Scan a local codebase
npx @mathiscode/codebase-scanner@latest local /path/to/codebase
npx @mathiscode/codebase-scanner@latest local --fix /path/to/codebase
Scan all dependencies of a codebase
npx @mathiscode/codebase-scanner@latest deps /path/to/codebase
Scan an npm package
npx @mathiscode/codebase-scanner@latest npm package-name
Scan a PyPI package
npx @mathiscode/codebase-scanner@latest pypi package-name
The tool will exit with a non-zero exit code if malicious code is found. This can be used to fail CI pipelines.
Exit Codes:
0
: No malicious code found
1
: Malicious code found
2
: Error
JSON Output
The tool can output a JSON array of detections. This can be used in more complex flows.
npx @mathiscode/codebase-scanner@latest local --json /path/to/codebase
[
{
"file": "/path/to/codebase/malware.js",
"triggered": true,
"level": "malicious",
"index": 3,
"name": "Obfuscated Javascript (Buffered \"child_process\")"
}
]
When a file is fixed (using the --fix
option with the local
command), the following header is prepended to the file:
========= MALICIOUS ========= [hidden unicode characters to help break loading]
This file has been flagged as malicious by https://github.com/mathiscode/codebase-scanner
Please review the file and remove these lines if appropriate.
========= MALICIOUS ========= [hidden unicode characters to help break loading]
Reasoning
This started as a quick and dirty tool to help defend against common developer-focused malware campaigns since many of these go unnoticed by common antivirus software.
A common scam is to have a developer "take a look" at a codebase or perform a "test task", and then it starts exfiltrating data.
When a signature is found, the filename is printed to the console and optionally fixed (if local --fix
is passed). When fixing, a header is prepended to the file to prevent the malware from running or being imported. This may not be foolproof, so always exercise caution and do everything possible to avoid letting the codebase run any scripts.
Inspired by this experience (obfuscated Javascript steals your browser profiles and other files via a "test task" on freelancing sites, hidden within a seemingly innocuous codebase).
PRs welcome!
Have you found a new signature? Please submit a PR with the signature added to signatures/
and a sample file in the samples/
directory. Currently, signature file 0.js
is Javascript signatures and 1.js
is Python signatures.
To see samples of some of these malicious codebases, check out this repository.