Here’s a comprehensive guide to mastering source code analysis with:
🔍 Manual code review techniques
🎯 Language-specific recommendations
🧨 Vulnerable Codebases for Practice
1. Vulnerable Web Applications with Source Code Access
These are perfect for:
Identifying insecure functions
Understanding common anti-patterns
Practicing code-level exploitation
These tools help automatically detect vulnerabilities in source code.
Fast, rule-based scanner, highly customizable
Full enterprise-grade code quality + security
Semantic code analysis with advanced query language
Privacy/security scanner, excellent for API and secrets issues
Go language security scanner
Java bytecode scanner with OWASP rules
Taint-Mode Tools (e.g., CodeQL)
Track data flow across sinks and sources
🔍 Manual Review Methodology
What to Look For:
eval(), exec(), raw SQL, unsanitized headers
Authentication/Authorization
Hardcoded creds, weak token logic, IDOR
Insecure cookies, session fixation
Passwords stored in plaintext, weak encryption
Homebrew crypto, ECB mode, missing IVs
Shell injection points (os.system, subprocess)
pickle.load(), Java readObject()
TOCTOU bugs, threading misuse
API keys, passwords in .env, .git or config files
Business logic errors, bypasses, incorrect conditions
Trace data flow from source (user input) to sink (DB, shell, etc.)
Review API endpoints, middleware, and helper utilities
Look for insecure defaults or commented-out protections
Check for inconsistent authentication or authorization checks
📦 Real-World Source Code Analysis Scenarios
Scenario
Language
How to Practice
WebGoat, vulnerable Flask App
SQL Injection via ORM Misuse
Secrets Leaking in Commits
Practice using truffleHog, git-secrets on GitHub repos
🧪 Automated Secrets & Token Discovery
Finds secrets in git repos
Secret scanning + custom rules
Pre-commit hook for secret detection
Secrets scanning across public/private repos (if enabled)
📚 Resources to Learn Source Code Review
The Art of Software Security Assessment (Book)
Framework-agnostic review practices
Practice writing your own detection rules
CodeQL Learning Lab (GitHub)
Create advanced security queries
PortSwigger Labs + Source View
Browse source + exploit live (Pro users)
HackTheBox Academy – Secure Coding
Great for building secure code review mindset
🎯 Language-Specific Advice
eval, insecure templates, prototype pollution
pickle, yaml.load, subprocess abuse
Variable variables, LFI/RFI, magic quotes
Deserialization, unsafe reflection
Lack of built-in auth, poor error handling
Insecure crypto APIs, config leaks
eval, mass assignment (params.permit!)
🔬 Advanced Manual Code Review Tactics
Beyond basic input validation, look for:
1. Inconsistent Authorization
Checks on the UI but not enforced on the backend.
Flawed if/else logic that causes unintended access:
3. Regex Bypass
4. Unsafe File Access
Watch for string concatenation in file paths:
5. Cryptographic Failures
🧠 Less Common but Critical Vulnerabilities to Look For
Logging secrets or tokens to logs (logger.debug(auth_token))
Admin features enabled via client-side toggle
Importing vulnerable libraries (e.g., event-stream in Node.js)
OAuth/OpenID misimplementation
Not validating aud, iss, exp in JWTs
Login timing difference revealing valid usernames
check_balance() → withdraw() in fast sequence
Insecure template rendering
Using render(request, user_input) (template injection)
🧪 Open-Source Projects You Can Practice On (Ethically)
These are security-focused or “bug bounty” friendly:
Mozilla Firefox (Bug Bounty Eligible)
Complex parsing logic, legacy components
Simple but real-world app
SecureDrop (Freedom of the Press Foundation)
Handles anonymity + encryption
Password manager code is rich in crypto logic
Great for OAuth, ActivityPub protocol abuse
Use case: content access control logic
Audit code and match findings to:
🚨 Real Vulnerabilities Found via Source Review
XSS in link previews inside encrypted messages
Command injection via internal CLI
Found via static analysis
Malicious dependency used in open source
Developers forgot to check alg=none
Found via manual token review
YAML config deserialization bug
⚙️ Source Code Review in CI/CD (DevSecOps Integration)
Tool
Best Used For
CI Integration
Code scanning, custom rules
GitHub Actions, GitLab CI, CircleCI
Built-in GitHub integration
Terraform, CloudFormation audits
Git pre-commit + PR check
Advanced data flow analysis
GitHub native or custom CI
💡 Tip: Set to fail builds only on high-severity findings or use a "monitor-only" mode.
👩💻 Bug Bounty Source Review (If You Have Source or Recon Access)
Focus on these techniques:
Attack Vector
What to Look For
.env, .js, .map, Vue/React bundles
Old endpoints in codebase
.map files or open-source client repos
company filename:.env or filename:docker-compose.yml
Accidental test code in production
Debug ports, credentials in staging branches
No rate limits, misauth, internal APIs exposed
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