frontend-security

Frontend Security Audit Skill

Perform comprehensive security audits of frontend codebases to identify vulnerabilities, bad practices, and missing protections.

Audit Process

1. Scan for dangerous patterns - Search codebase for known vulnerability indicators
2. Review framework-specific risks - Check for framework security bypass patterns
3. Validate defensive measures - Verify CSP, CSRF tokens, input validation
4. Check dependencies - Review npm/node dependencies for vulnerabilities
5. Report findings - Categorize by severity with remediation guidance

Critical Vulnerability Patterns to Search

XSS Indicators (Search Priority: HIGH)

# React dangerous patterns
grep -rn "dangerouslySetInnerHTML" --include="*.jsx" --include="*.tsx" --include="*.js"

# Direct DOM manipulation
grep -rn "\.innerHTML\s*=" --include="*.js" --include="*.ts" --include="*.jsx" --include="*.tsx"
grep -rn "\.outerHTML\s*=" --include="*.js" --include="*.ts"
grep -rn "document\.write" --include="*.js" --include="*.ts"

# URL-based injection
grep -rn "location\.href\s*=" --include="*.js" --include="*.ts"
grep -rn "location\.replace" --include="*.js" --include="*.ts"
grep -rn "window\.open" --include="*.js" --include="*.ts"

# Eval and code execution
grep -rn "eval\s*(" --include="*.js" --include="*.ts"
grep -rn "new Function\s*(" --include="*.js" --include="*.ts"
grep -rn "setTimeout\s*(\s*['\"]" --include="*.js" --include="*.ts"
grep -rn "setInterval\s*(\s*['\"]" --include="*.js" --include="*.ts"

# Twig unescaped output
grep -rn "|raw" --include="*.twig" --include="*.html.twig"
grep -rn "{% autoescape false %}" --include="*.twig"

CSRF Indicators

# Forms without CSRF tokens
grep -rn "<form" --include="*.html" --include="*.jsx" --include="*.tsx" --include="*.twig"

# State-changing requests without protection
grep -rn "fetch\s*(" --include="*.js" --include="*.ts" | grep -E "(POST|PUT|DELETE|PATCH)"
grep -rn "axios\.(post|put|delete|patch)" --include="*.js" --include="*.ts"