Ensure pull_request_target workflows do not check out or run untrusted pull request code

CritiqueNiveau 1Automatiséesupply-chain

Description

pull_request_target runs in the context of the base repository with a write-scoped GITHUB_TOKEN and access to secrets. Checking out the PR head (github.event.pull_request.head.sha/ref, github.head_ref, refs/pull/*) and building it lets any fork author execute code with those privileges ('pwn request'). The audit flags workflow files that use pull_request_target and reference the PR head anywhere; review flagged files manually.

Méthode de vérification

Méthode d'audit: Commande shell

shell

top=$(git rev-parse --show-toplevel 2>/dev/null) || exit 1
cd "$top" || exit 1
wf=$(git ls-files -- '.github/workflows/*.yml' '.github/workflows/*.yaml' 2>/dev/null) || exit 1
bad=$(printf '%s\n' "$wf" | while IFS= read -r f; do
  [ -n "$f" ] || continue
  if grep -qE '^[^#]*pull_request_target' "$f" &&
     grep -qE '^[^#]*(github\.event\.pull_request\.head\.(sha|ref|repo)|github\.event\.pull_request\.merge_commit_sha|github\.head_ref|refs/pull/)' "$f"; then
    echo "$f"
  fi
done)
if [ -z "$bad" ]; then echo compliant; else echo "pull_request_target workflows that reference the untrusted PR head:"; printf '%s\n' "$bad"; fi

Sortie attendue: compliant

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

Switch the workflow to the pull_request trigger (no secrets, read-only token), or split it: build untrusted code under pull_request and upload artifacts, then process them in a separate workflow_run job that never executes PR code. If pull_request_target is unavoidable, do not check out the head ref and set permissions: read-all.

Propriétés

Systèmes d'exploitation: Tous
Étiquettes: supply-chainbuild-pipelinegithub-actions
Référence: CIS Software Supply Chain Security Guide Benchmark v1.0.0 - Build Pipelines - isolate untrusted code from pipeline secrets (verify section number for your release)

Vérifier cet hôte

Exécutez cette commande sur une machine que vous êtes autorisé à auditer. L'analyse est en lecture seule.

shell

tmaegis scan --target supply-chain