security-pen-testing

Security Penetration Testing

Hands-on offensive security testing skill for finding vulnerabilities before attackers do. This is NOT compliance checking (see senior-secops) or security policy writing (see senior-security) — this is about systematic vulnerability discovery through authorized testing.

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Table of Contents

• [Overview](#overview)
• [OWASP Top 10 Systematic Audit](#owasp-top-10-systematic-audit)
• [Static Analysis](#static-analysis)
• [Dependency Vulnerability Scanning](#dependency-vulnerability-scanning)
• [Secret Scanning](#secret-scanning)
• [API Security Testing](#api-security-testing)
• [Web Vulnerability Testing](#web-vulnerability-testing)
• [Infrastructure Security](#infrastructure-security)
• [Pen Test Report Generation](#pen-test-report-generation)
• [Responsible Disclosure Workflow](#responsible-disclosure-workflow)
• [Workflows](#workflows)
• [Anti-Patterns](#anti-patterns)
• [Cross-References](#cross-references)

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Overview

What This Skill Does

This skill provides the methodology, checklists, and automation for offensive security testing — actively probing systems to discover exploitable vulnerabilities. It covers web applications, APIs, infrastructure, and supply chain security.

Distinction from Other Security Skills

| Skill | Focus | Approach |

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

| security-pen-testing (this) | Finding vulnerabilities | Offensive — simulate attacker techniques |

| senior-secops | Security operations | Defensive — monitoring, incident response, SIEM |

| senior-security | Security policy | Governance — policies, frameworks, risk registers |

| skill-security-auditor | CI/CD gates | Automated — pre-merge security checks |

Prerequisites

All testing described here assumes written authorization from the system owner. Unauthorized testing is illegal under the CFAA and equivalent laws worldwide. Always obtain a signed scope-of-work or rules-of-engagement document before starting.

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OWASP Top 10 Systematic Audit

Use the vulnerability scanner tool for automated checklist generation:

# Generate OWASP checklist for a web application
python scripts/vulnerability_scanner.py --target web --scope full

# Quick API-focused scan
python scripts/vulnerability_scanner.py --target api --scope quick --json

Quick Reference

| # | Category | Key Tests |

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

| A01 | Broken Access Control | IDOR, vertical escalation, CORS, JWT claim manipulation, forced browsing |

| A02 | Cryptographic Failures | TLS version, password hashing, hardcoded keys, weak PRNG |

| A03 | Injection | SQLi, NoSQLi, command injection, template injection, XSS |

| A04 | Insecure Design | Rate limiting, business logic abuse, multi-step flow bypass |

| A05 | Security Misconfiguration | Default credentials, debug mode, security headers, directory listing |

| A06 | Vulnerable Components | Dependency audit (npm/pip/go), EOL checks, known CVEs |

| A07 | Auth Failures | Brute force, session cookie flags, session invalidation, MFA bypass |

| A08 | Integrity Failures | Unsafe deserialization, SRI checks, CI/CD pipeline integrity |

| A09 | Logging Failures | Auth event logging, sensitive data in logs, alerting thresholds |

| A10 | SSRF | Internal IP access, cloud metadata endpoints, DNS rebinding |

# Audit dependencies
python scripts/dependency_auditor.py --file package.json --severity high
python scripts/dependency_auditor.py --file requirements.txt --json

See [owasp_top_10_checklist.md](references/owasp_top_10_checklist.md) for detailed test procedures, code patterns to detect, remediation steps, and CVSS scoring guidance for each category.

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Static Analysis

Recommended tools: CodeQL (custom queries for project-specific patterns), Semgrep (rule-based scanning with auto-fix), ESLint security plugins (eslint-plugin-security, eslint-plugin-no-unsanitized).

Key patterns to detect: SQL injection via string concatenation, hardcoded JWT secrets, unsafe YAML/pickle deserialization, missing security middleware (e.g., Express without Helmet).

See [attack_patterns.md](references/attack_patterns.md) for code patterns and detection payloads across injection types.

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Dependency Vulnerability Scanning

Ecosystem commands: npm audit, pip audit, govulncheck ./..., bundle audit check

CVE Triage Workflow:

1. Collect — Run ecosystem audit tools, aggregate findings
2. Deduplicate — Group by CVE ID across direct and transitive deps
3. Prioritize — Critical + exploitable + reachable = fix immediately
4. Remediate — Upgrade, patch, or mitigate with compensating controls
5. Verify — Rerun audit to confirm fix, update lock files

python scripts/dependency_auditor.py --file package.json --severity critical --json

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Secret Scanning

Tools: TruffleHog (git history + filesystem), Gitleaks (regex-based with custom rules).

# Scan git history for verified secrets
trufflehog git file://. --only-verified --json

# Scan filesystem
trufflehog filesystem . --json

Integration points: Pre-commit hooks (gitleaks, trufflehog), CI/CD gates (GitHub Actions with trufflesecurity/trufflehog@main). Configure .gitleaks.toml for custom rules (AWS keys, API keys, private key headers) and allowlists for test fixtures.

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API Security Testing

Authentication Bypass

• JWT manipulation: Change alg to none, RS256-to-HS256 confusion, claim modification (role: "admin", exp: 9999999999)
• Session fixation: Check if session ID changes after authentication

Authorization Flaws

• IDOR/BOLA: Change resource IDs in every endpoint — test read, update, delete across users
• BFLA: Regular user tries admin endpoints (expect 403)
• Mass assignment: Add privileged fields (role, is_admin) to update requests

Rate Limiting & GraphQL

• Rate limiting: Rapid-fire requests to auth endpoints; expect 429 after threshold
• GraphQL: Test introspection (should be disabled in prod), query depth attacks, batch mutations bypassing rate limits

See [attack_patterns.md](references/attack_patterns.md) for complete JWT manipulation payloads, IDOR testing methodology, BFLA endpoint lists, GraphQL introspection/depth/batch attack patterns, and rate limiting bypass techniques.

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Web Vulnerability Testing

| Vulnerability | Key Tests |

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

| XSS | Reflected (script/img/svg payloads), Stored (persistent fields), DOM-based (innerHTML + location.hash) |

| CSRF | Replay without token (expect 403), cross-session token replay, check SameSite cookie attribute |

| SQL Injection | Error-based (' OR 1=1--), union-based enumeration, time-based blind (SLEEP(5)), boolean-based blind |

| SSRF | Internal IPs, cloud metadata endpoints (AWS/GCP/Azure), IPv6/hex/decimal encoding bypasses |

| Path Traversal | ../../../etc/passwd, URL encoding, double encoding bypasses |

See [attack_patterns.md](references/attack_patterns.md) for complete test payloads (XSS filter bypasses, context-specific XSS, SQL injection per database engine, SSRF bypass techniques, and DOM-based XSS source/sink pairs).

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Infrastructure Security

Key checks:

• Cloud storage: S3 bucket public access (aws s3 ls s3://bucket --no-sign-request), bucket policies, ACLs
• HTTP security headers: HSTS, CSP (no unsafe-inline/unsafe-eval), X-Content-Type-Options, X-Frame-Options, Referrer-Policy
• TLS configuration: nmap --script ssl-enum-ciphers -p 443 target.com or testssl.sh — reject TLS 1.0/1.1, RC4, 3DES, export-grade ciphers
• Port scanning: nmap -sV target.com — flag dangerous open ports (FTP/21, Telnet/23, Redis/6379, MongoDB/27017)

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Pen Test Report Generation

Generate professional reports from structured findings:

# Generate markdown report from findings JSON
python scripts/pentest_report_generator.py --findings findings.json --format md --output report.md

# Generate JSON report
python scripts/pentest_report_generator.py --findings findings.json --format json --output report.json

Findings JSON Format

[
  {
    "title": "SQL Injection in Login Endpoint",
    "severity": "critical",
    "cvss_score": 9.8,
    "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "category": "A03:2021 - Injection",
    "description": "The /api/login endpoint is vulnerable to SQL injection via the email parameter.",
    "evidence": "Request: POST /api/login {\"email\": \"' OR 1=1--\", \"password\": \"x\"}\nResponse: 200 OK with admin session token",
    "impact": "Full database access, authentication bypass, potential remote code execution",
    "remediation": "Use parameterized queries. Replace string concatenation with prepared statements.",
    "references": ["https://cwe.mitre.org/data/definitions/89.html"]
  }
]

Report Structure

1. Executive Summary: Business impact, overall risk level, top 3 findings
2. Scope: What was tested, what was excluded, testing dates
3. Methodology: Tools used, testing approach (black/gray/white box)
4. Findings Table: Sorted by severity with CVSS scores
5. Detailed Findings: Each with description, evidence, impact, remediation
6. Remediation Priority Matrix: Effort vs. impact for each fix
7. Appendix: Raw tool output, full payload lists

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Responsible Disclosure Workflow

Responsible disclosure is mandatory for any vulnerability found during authorized testing. Standard timeline: report on day 1, follow up at day 7, status update at day 30, public disclosure at day 90.

Key principles: Never exploit beyond proof of concept, encrypt all communications, do not access real user data, document everything with timestamps.

See [responsible_disclosure.md](references/responsible_disclosure.md) for full disclosure timelines (standard 90-day, accelerated 30-day, extended 120-day), communication templates, legal considerations, bug bounty program integration, and CVE request process.

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Workflows

Workflow 1: Quick Security Check (15 Minutes)

For pre-merge reviews or quick health checks:

# 1. Generate OWASP checklist
python scripts/vulnerability_scanner.py --target web --scope quick

# 2. Scan dependencies
python scripts/dependency_auditor.py --file package.json --severity high

# 3. Check for secrets in recent commits
# (Use gitleaks or trufflehog as described in Secret Scanning section)

# 4. Review HTTP security headers
curl -sI https://target.com | grep -iE "(strict-transport|content-security|x-frame|x-content-type)"

Decision: If any critical or high findings, block the merge.

Workflow 2: Full Penetration Test (Multi-Day Assessment)

Day 1 — Reconnaissance:

1. Map the attack surface: endpoints, authentication flows, third-party integrations
2. Run automated OWASP checklist (full scope)
3. Run dependency audit across all manifests
4. Run secret scan on full git history

Day 2 — Manual Testing:

1. Test authentication and authorization (IDOR, BOLA, BFLA)
2. Test injection points (SQLi, XSS, SSRF, command injection)
3. Test business logic flaws
4. Test API-specific vulnerabilities (GraphQL, rate limiting, mass assignment)

Day 3 — Infrastructure and Reporting:

1. Check cloud storage permissions
2. Verify TLS configuration and security headers
3. Port scan for unnecessary services
4. Compile findings into structured JSON
5. Generate pen test report

# Generate final report
python scripts/pentest_report_generator.py --findings findings.json --format md --output pentest-report.md

Workflow 3: CI/CD Security Gate

Automated security checks on every PR: secret scanning (TruffleHog), dependency audit (npm audit, pip audit), SAST (Semgrep with p/security-audit, p/owasp-top-ten), and security headers check on staging.

Gate Policy: Block merge on critical/high findings. Warn on medium. Log low/info.

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Anti-Patterns

1. Testing in production without authorization — Always get written permission and use staging/test environments when possible
2. Ignoring low-severity findings — Low findings compound; a chain of lows can become a critical exploit path
3. Skipping responsible disclosure — Every vulnerability found must be reported through proper channels
4. Relying solely on automated tools — Tools miss business logic flaws, chained exploits, and novel attack vectors
5. Testing without a defined scope — Scope creep leads to legal liability; document what is and isn't in scope
6. Reporting without remediation guidance — Every finding must include actionable remediation steps
7. Storing evidence insecurely — Pen test evidence (screenshots, payloads, tokens) is sensitive; encrypt and restrict access
8. One-time testing — Security testing must be continuous; integrate into CI/CD and schedule periodic assessments

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Cross-References

| Skill | Relationship |

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

| [senior-secops](../senior-secops/SKILL.md) | Defensive security operations — monitoring, incident response, SIEM configuration |

| [senior-security](../senior-security/SKILL.md) | Security policy and governance — frameworks, risk registers, compliance |

| [dependency-auditor](engineering/skills/dependency-auditor/SKILL.md) | Deep supply chain security — SBOMs, license compliance, transitive risk |

| [code-reviewer](../code-reviewer/SKILL.md) | Code review practices — includes security review checklist |