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Malicious Code in Open Source: How to Detect It Before You Ship | Blog | Endor Labs
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Malicious Code in Open Source: How to Detect It Before You Ship | Blog | Endor Labs

Endor Labs explains the two dominant classes of OSS malware attacks - dependency/name confusion (typosquatting, combo-squatting, brand-jacking) and attacks on legitimate packages/maintainers - and how the OpenSSF malware-analysis project sandboxes new PyPI/npm releases and reports confirmed malware to OSV. It walks through real cases it detected, including the chunked/split-across-files PyPI malware ttlo and gisi, and Whatfuscator which drops and runs a PyInstaller-built Windows executable, plus two false-positive suspicious-code flags (versioneer 0.29, azure-functions 1.18.0) caused by benign base64/zlib obfuscation.

TL;DR Endor Labs breaks down dependency/name-confusion vs. legitimate-package-compromise malware, with real PyPI case studies (ttlo, gisi, Whatfuscator) and two benign obfuscation false positives, before pitching its own scanner.

Organisations named here

  • azure-functions
  • gisi
  • OpenSSF malware-analysis
  • ttlo
  • versioneer
  • werkzeug

Technologies named here

  • Endor Labs Open Source
  • PyPI
  • npm
  • OpenSSF malware-analysis project
  • versioneer@0.29
  • OSV
  • azure-functions@1.18.0
  • PyPI Stats
  • GitHub Dependabot
  • PyInstaller
  • Python
  • Endor Labs
  • Windows

Techniques named here

  • Dependency confusion attacks
  • Name confusion attacks
  • Splitting malicious code across multiple files/packages
  • Downloading and executing a remote payload
  • Code obfuscation via Base64 encoding and compression
  • Attacks on legitimate packages

Threat actors named here

  • ttlo and gisi
  • Whatfuscator
  • bobikssf
  • Malicious GitHub Dependabot impersonation campaign