find-security-vulnerabilities-in-code

Find security vulnerabilities in code

White-box security review with Strix: the agents read the source to build a model of routes, sinks, and authorization checks, then attempt real exploitation. Findings come with a proof-of-concept, so the output is a short list of proven issues rather than the hundreds of "potential" hits a pattern-matching scanner produces.

Install, LLM setup, all flags, and the managed-cloud path are in the penetration-testing-with-strix skill.

Run it

# Local working tree
strix -n -t ./ --scan-mode standard --max-budget 15

# A GitHub repo directly
strix -n -t https://github.com/org/app --max-budget 15

# Monorepo: point at the service that matters, not the whole tree
strix -n -t ./services/checkout --max-budget 20

# Only what a branch changed (whole-repo review is wasteful on a large repo)
strix -n -t ./ --scope-mode diff --diff-base origin/main --max-budget 10

A local path is mounted into the sandbox writable, so the agents can modify it. Run against a clean checkout.

Two things sharply improve results:

1. Add a running instance of the app. -t ./ -t http://host.docker.internal:3000 lets the agents confirm exploitability against live behavior instead of reasoning about it statically — this is the difference between "this looks unsafe" and a validated finding. If nothing is running, static-only findings should be described as unconfirmed.
2. Scope the review. Point at the risky subtree and say what matters:

   strix -n -t ./services/api --max-budget 15 \
     --instruction "Focus on the authorization layer in src/auth and every route under src/routes/admin. Multi-tenant app: tenant id comes from the JWT. Flag any query that filters by object id without also filtering by tenant."
   

   Tenancy model, trust boundaries, and which inputs are attacker-controlled are things the agents cannot infer reliably — tell them.

Reviewing a pull request instead of the whole repo

For diff-scoped review of a branch or PR (and blocking merges on findings), use ci-security-scanning-with-strix — it covers diff scoping, PR comments, and SARIF upload to GitHub code scanning. The managed platform can also review PRs directly via API (managed-pentesting-with-strix).