I attacked my own secret scanner and 7 of 8 tricks worked

Description and use

Tripwire, a secret scanner, was attacked via a pull request that edited ignore files and baseline, a symlink, a crafted file, and a local API. After fixes and tests, the vulnerabilities were removed.

Problem

A secret scanner (Tripwire) could be bypassed by a pull request that edits ignore files or baseline, allowing a PR to add a key while hiding it from the scan.

Outcome

After testing eight attack vectors, seven succeeded in bypassing Tripwire. Fixes were implemented and regression tests added, restoring Tripwire’s integrity against PR‑based attacks.

Workflow

• 1. Create a PR that edits .tripwireignore or baseline to ignore the file containing a new key.
• 2. Run Tripwire as a pre‑commit hook or GitHub Action.
• 3. Observe that the check passes because the key is hidden.
• 4. Apply fixes: disallow PRs from modifying ignore files, ignore symlinks, add test for crafted file, secure local API.
• 5. Re‑run Tripwire to confirm the key is detected and the check fails.

Evidence

Tripwire honors a .tripwireignore file and a baseline file so teams can adopt it on an old codebase without a wall of red.

Source

A symlink pointing outside the repo was followed, so scanning a hostile repo meant reading files from the machine doing the scan.

Source

A single file I built on purpose made the scanner hang for 22 seconds.

Source

The web UI talks to a local API with endpoints that scan repos and can trigger revocation. It was reachable by anyone on the same network.

Source