Sec Code Audit

When to use

Use this before merging security-sensitive changes, when reviewing untrusted or legacy code, or during a scheduled appsec pass. The goal is to find defensive weaknesses and recommend fixes.

Not for: writing working exploits or PoCs; scanning dependencies for CVEs (use sec-dependency-audit); or architecture-level risk enumeration (use sec-threat-model). Review the code you can read — do not attack a running system.

Method

1. Map inputs and sinks. Trace where external data enters (requests, files, env, messages) and where it reaches dangerous sinks (SQL, shell, eval, file paths, HTML, deserializers, template engines).
2. Injection. Confirm parameterized queries, escaped output, allow-listed commands, and safe path joins. Decision point: any string-concatenated query, shell call, or dynamic template is a finding until proven safe.
3. AuthN/AuthZ. Verify every privileged action checks identity AND permission server-side. Hunt for missing checks, IDOR (object references without ownership checks), and client-trusted roles.
4. Secrets. Look for hardcoded keys, tokens, passwords, and any secret written to logs or returned to clients. Confirm secrets load from config or a vault.
5. Deserialization & parsing. Flag unsafe deserialization (pickle, native serialize, YAML unsafe load), XXE-prone XML parsers, and prototype pollution.
6. Crypto & sessions. Decision point: if you see a hand-rolled cipher, MD5/SHA1 for passwords, or a predictable token, escalate to Critical and stop to confirm blast radius before continuing.

Example

In getInvoice(req) you find db.query("SELECT * FROM invoices WHERE id=" + req.params.id). Finding: SQL injection, Critical, invoice.js:42, category Injection. Fix: use a parameterized query — db.query("SELECT * FROM invoices WHERE id=?", [req.params.id]). Also note the missing ownership check (IDOR) — any user can read any invoice id.

Pitfalls

• Grepping for eval and stopping. Real injection hides behind wrappers and helpers; follow the data, not the keyword.
• Reporting without a fix. A finding with no concrete remediation gets ignored. Always include the corrected pattern.
• Trusting framework defaults blindly. ORMs and templates have raw-query and raw-HTML escape hatches; check whether they are used.
• Severity inflation. Marking everything Critical trains reviewers to ignore you. Rank honestly by impact and reachability.

Output format

## Summary
Files reviewed: <list>. Overall risk posture: <sentence>.

## Findings
| Severity | File:line | Category | Description | Recommended fix |
|----------|-----------|----------|-------------|-----------------|

## Quick wins
- <low-effort, high-value fix>

## Follow-ups
- <needs design change or owner decision>