# Secure Coding

> Review code for OWASP Top 10 vulnerabilities and secure coding practices

- Skill: `bromso/secure-coding` (Agent Skill)
- Install (CLI): `npx skillmds@latest add bromso/secure-coding`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bromso/secure-coding/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: bromso (https://skillmd.com/u/bromso)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/bromso/secure-coding

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# Secure Coding

Review code for OWASP Top 10 vulnerabilities and secure coding practices for "$ARGUMENTS". Identify security weaknesses in application code and recommend remediations aligned with industry standards.

## Prerequisites

Read `.metapowers/security/$ARGUMENTS/00-govern.md`. If this file does not exist, tell the user:

> Phase 0 (Govern) has not been completed for "$ARGUMENTS". Run a Govern skill first (e.g., `/security:security-policy $ARGUMENTS`), or use `--skip-checks` to bypass.

If `--skip-checks` is present in $ARGUMENTS, skip this check and log to `.metapowers/security/$ARGUMENTS/skip-log.md`.

## Process

1. **Identify code to review:**
   - Determine the application language(s), framework(s), and entry points
   - Prioritize security-sensitive areas: authentication, authorization, data handling, API endpoints, file operations
   - Identify third-party integrations and trust boundaries

2. **Check against OWASP Top 10:**
   - **Injection** — SQL, NoSQL, OS command, LDAP injection via unsanitized input
   - **Broken Authentication** — weak password policies, credential stuffing exposure, session fixation
   - **Sensitive Data Exposure** — plaintext secrets, weak cryptography, missing encryption at rest or in transit
   - **XML External Entities (XXE)** — unsafe XML parsing, external entity processing enabled
   - **Broken Access Control** — missing authorization checks, IDOR, privilege escalation paths
   - **Security Misconfiguration** — default credentials, verbose error messages, unnecessary features enabled
   - **Cross-Site Scripting (XSS)** — reflected, stored, and DOM-based XSS via unescaped output
   - **Insecure Deserialization** — untrusted data deserialized without validation
   - **Using Components with Known Vulnerabilities** — outdated libraries with published CVEs
   - **Insufficient Logging and Monitoring** — missing audit trails for security events

3. **Review input validation and output encoding:**
   - Verify all user input is validated (allowlists preferred over denylists)
   - Check output encoding appropriate to context (HTML, URL, JavaScript, SQL)
   - Confirm parameterized queries or ORM usage for all database interactions
   - Review file upload handling (type validation, size limits, storage isolation)

4. **Review authentication and session management:**
   - Password hashing algorithm (bcrypt, scrypt, argon2 — not MD5/SHA1)
   - Session token generation (cryptographically random, sufficient entropy)
   - Session expiration and invalidation on logout
   - Multi-factor authentication implementation if applicable

5. **Review error handling:**
   - Confirm no stack traces, internal paths, or database details leaked in responses
   - Verify generic error messages for end users with detailed logging server-side
   - Check exception handling covers all code paths (no unhandled exceptions exposing internals)

6. **Review secure headers and transport security:**
   - Content-Security-Policy, X-Content-Type-Options, X-Frame-Options, Strict-Transport-Security
   - CORS configuration (no wildcard origins for authenticated endpoints)
   - Cookie flags (Secure, HttpOnly, SameSite)

7. **Write the artifact** to `.metapowers/security/$ARGUMENTS/02-protect.md` with heading:

   ## Secure Coding Review

   Include sections:
   - **Scope** — code areas reviewed, languages, and frameworks
   - **OWASP Top 10 Findings** — each vulnerability category with status (pass/fail/n/a) and details
   - **Input Validation Assessment** — validation coverage and gaps
   - **Authentication Review** — findings on auth and session management
   - **Error Handling Review** — information leakage risks
   - **Remediation Plan** — prioritized fixes with severity and effort estimate

## Output

The secure coding review written to `.metapowers/security/$ARGUMENTS/02-protect.md`. Present a summary to the user highlighting:
- Total findings by severity (critical, high, medium, low)
- OWASP Top 10 categories with identified issues
- Top priority remediations with effort estimates
- Secure coding practices already in place