Security Audit Skill

Perform security audits on codebases. Adapted from Trail of Bits security research methodology.

When to Use

• Security review before deployment
• Code audit for vulnerabilities
• Dependency vulnerability check
• Infrastructure/config security review
• Portfolio project security hardening

Audit Phases

Phase 1: Reconnaissance

Understand the codebase before scanning:

# Language detection
find . -type f | sed 's/.*\.//' | sort | uniq -c | sort -rn | head -20

# Framework detection
ls package.json pyproject.toml Gemfile go.mod Cargo.toml requirements.txt 2>/dev/null

# Entry points
grep -r "app.listen\|createServer\|Flask(\|FastAPI(\|func main" --include="*.py" --include="*.js" --include="*.ts" --include="*.go" -l

# Environment and secrets files
find . -name ".env*" -o -name "*.pem" -o -name "*.key" -o -name "*secret*" -o -name "*credential*" | grep -v node_modules | grep -v .git

Phase 2: Automated Scanning

Secrets Detection:

# Grep for common secret patterns
grep -rn "API_KEY\|SECRET\|PASSWORD\|TOKEN\|PRIVATE_KEY\|aws_access\|ssh-rsa" --include="*.py" --include="*.js" --include="*.ts" --include="*.env" --include="*.yaml" --include="*.yml" --include="*.json" . | grep -v node_modules | grep -v .git | grep -v "*.example"

Dependency Vulnerabilities:

# Node.js
npm audit --json 2>/dev/null | head -100

# Python
pip-audit 2>/dev/null || pip install pip-audit && pip-audit

# Check for outdated deps
npm outdated 2>/dev/null
pip list --outdated 2>/dev/null

Common Vulnerability Patterns (grep-based):

# SQL Injection (string concatenation in queries)
grep -rn "execute.*+\|execute.*%\|execute.*f'" --include="*.py" .
grep -rn "query.*+\|query.*\`" --include="*.js" --include="*.ts" .

# XSS (innerHTML, dangerouslySetInnerHTML)
grep -rn "innerHTML\|dangerouslySetInnerHTML\|v-html\|\$sce.trustAsHtml" --include="*.js" --include="*.ts" --include="*.jsx" --include="*.tsx" --include="*.vue" .

# Command Injection
grep -rn "exec(\|system(\|popen(\|subprocess.call\|child_process" --include="*.py" --include="*.js" --include="*.ts" .

# Path Traversal
grep -rn "\.\./" --include="*.py" --include="*.js" --include="*.ts" . | grep -v node_modules | grep -v test

# Hardcoded credentials
grep -rn "password.*=.*['\"].\+['\"]" --include="*.py" --include="*.js" --include="*.ts" --include="*.yaml" . | grep -v node_modules | grep -v test | grep -v example

Phase 3: Infrastructure Review

# Dockerfile issues
grep -n "FROM.*latest\|--no-check-certificate\|curl.*\|.*http:" Dockerfile* 2>/dev/null

# CORS configuration
grep -rn "Access-Control-Allow-Origin.*\*\|cors({.*origin.*true\|CORS(.*allow_all" --include="*.py" --include="*.js" --include="*.ts" .

# TLS/SSL
grep -rn "verify.*False\|rejectUnauthorized.*false\|NODE_TLS_REJECT_UNAUTHORIZED" --include="*.py" --include="*.js" --include="*.ts" .

# Rate limiting (absence is a finding)
grep -rn "rateLimit\|rate.limit\|throttle\|slowDown" --include="*.py" --include="*.js" --include="*.ts" . || echo "WARNING: No rate limiting detected"

Phase 4: Manual Review Focus Areas

Based on OWASP Top 10 (2021):

1. A01 Broken Access Control — Check auth middleware, route protection, IDOR patterns
2. A02 Cryptographic Failures — Weak hashing (MD5/SHA1 for passwords), missing encryption
3. A03 Injection — SQL, NoSQL, OS command, LDAP injection
4. A04 Insecure Design — Missing input validation, trust boundary violations
5. A05 Security Misconfiguration — Debug mode, default credentials, verbose errors
6. A06 Vulnerable Components — Outdated dependencies with known CVEs
7. A07 Auth Failures — Weak password policy, missing MFA, session fixation
8. A08 Data Integrity Failures — Unsigned updates, insecure deserialization
9. A09 Logging Failures — Missing audit logs, logging sensitive data
10. A10 SSRF — Unvalidated URL inputs, internal service access

Report Format

# Security Audit Report
**Project:** [name]
**Date:** [date]
**Scope:** [files/components audited]

## Executive Summary
[1-2 sentences: overall security posture]

## Critical Findings
### [CRITICAL-001] [Title]
- **Severity:** Critical/High/Medium/Low/Info
- **Category:** OWASP A0X
- **Location:** file:line
- **Description:** What's wrong
- **Impact:** What an attacker could do
- **Remediation:** How to fix it
- **Code:** [before/after snippets]

## Summary Table
| ID | Severity | Category | Title | Status |
|----|----------|----------|-------|--------|
| C-001 | Critical | A03 | SQL Injection in user search | Open |

## Recommendations
[Prioritized list of security improvements]

Limitations

• Grep-based scanning has high false positive rate; manual verification required
• Cannot detect logic flaws or business logic vulnerabilities
• Does not replace professional penetration testing
• No runtime analysis (DAST); static only