Next js Security Scan Agent Skill

Next.js Security Scan Skill

This skill enables comprehensive security scanning of Next.js and TypeScript/JavaScript projects based on OWASP guidelines and industry best practices.

When to Use This Skill

• Security audits of Next.js applications
• Code review for security vulnerabilities
• Pre-deployment security checks
• Dependency vulnerability assessment
• Detecting hardcoded secrets and credentials

Scan Types

1. Quick Scan

Fast scan focusing on critical vulnerabilities:

• Hardcoded secrets and API keys
• Dangerous function usage (dangerouslySetInnerHTML, eval)
• Missing authentication in Server Actions
• Known vulnerable dependencies

2. Full Scan

Comprehensive security assessment covering:

• All OWASP Top 10:2025 categories
• XSS vulnerability patterns
• Injection vulnerabilities (SQL, NoSQL, Command)
• Authentication and authorization flaws
• Security misconfigurations
• Cryptographic failures
• Next.js-specific vulnerabilities
• Dependency audit (CVE check)
• Environment variable exposure

3. Targeted Scan

Focus on specific vulnerability categories:

• --xss - Cross-site scripting patterns
• --injection - SQL/NoSQL/Command injection
• --auth - Authentication/authorization issues
• --secrets - Hardcoded credentials
• --deps - Dependency vulnerabilities
• --nextjs - Next.js specific issues

Scan Procedure

Step 1: Project Discovery

• Identify project type (Next.js App Router, Pages Router, or plain React)
• Locate configuration files (next.config.js, package.json, .env*)
• Map the codebase structure

Step 2: Dependency Audit

Run the dependency audit script:

./scripts/dependency-audit.sh

Or manually:

npm audit --json
# or
yarn audit --json

Step 3: Secret Scanning

Scan for hardcoded secrets:

python scripts/secret-scanner.py /path/to/project

Important: Environment File Handling

• By default, real .env files are SKIPPED (.env, .env.local, .env.production, etc.)
• These files contain actual secrets and should not be in version control
• Only .env.example and .env.template files are analyzed for documentation quality
• Use --include-env-files flag only if explicitly requested by user

The scanner will:

• Scan source code for hardcoded secrets
• Analyze .env.example templates to check:
• Which sensitive variables are documented
• Whether variables have descriptions (comments)
• If placeholder values look like real secrets
• Suggestions for missing common variables

Step 4: Pattern Analysis

For each file in the codebase, check against patterns in:

• references/xss-patterns.md - XSS vulnerabilities
• references/injection-patterns.md - Injection flaws
• references/auth-vulnerabilities.md - Auth issues
• references/nextjs-specific.md - Next.js vulnerabilities

Step 5: Report Generation

Generate a security report using:

• assets/report-template.md - Report structure

Severity Classification

| Severity | Description | Action Required |

|----------|-------------|-----------------|

| CRITICAL | Exploitable vulnerability with severe impact | Immediate fix required |

| HIGH | Significant security risk | Fix before deployment |

| MEDIUM | Potential security issue | Fix in next release |

| LOW | Minor security concern | Consider fixing |

| INFO | Security best practice suggestion | Optional improvement |

Key Files to Scan

Always Check

• /*.ts, /*.tsx, /*.js, /*.jsx - Source code
• next.config.js, next.config.mjs - Next.js configuration
• package.json, package-lock.json - Dependencies
• middleware.ts, middleware.js - Middleware security

Environment Files

• .env.example, .env.template - SCAN for template analysis
• .env, .env.local, .env.production - SKIP by default (contain real secrets)

Note: Real .env files should never be committed to version control. The scanner analyzes .env.example templates to ensure proper documentation of required variables.

High Priority Locations

• app/api/**/* - API routes (App Router)
• pages/api/**/* - API routes (Pages Router)
• /actions.ts, /*-actions.ts - Server Actions
• lib/auth*, utils/auth* - Authentication code
• **/middleware.* - Middleware files

Output Format

Findings should be reported as:

[SEVERITY] Category: Description
  File: path/to/file.ts:lineNumber
  Code: <relevant code snippet>
  Risk: <explanation of the security risk>
  Fix: <recommended remediation>

Integration with CI/CD

This skill can generate output compatible with:

• GitHub Security Advisories
• SARIF format for GitHub Code Scanning
• JSON for custom integrations

References

Load additional context as needed:

• references/owasp-top-10.md - OWASP Top 10:2025 quick reference
• references/xss-patterns.md - XSS detection patterns
• references/injection-patterns.md - Injection vulnerability patterns
• references/auth-vulnerabilities.md - Authentication security patterns
• references/nextjs-specific.md - Next.js specific vulnerabilities and CVEs