Security Review

Security Review Skill

Identify exploitable security vulnerabilities in code. Report only HIGH CONFIDENCE findings—clear vulnerable patterns with attacker-controlled input.

Scope: Research vs. Reporting

CRITICAL DISTINCTION:

• Report on: Only the specific file, diff, or code provided by the user
• Research: The ENTIRE codebase to build confidence before reporting

Before flagging any issue, you MUST research the codebase to understand:

• Where does this input actually come from? (Trace data flow)
• Is there validation/sanitization elsewhere?
• How is this configured? (Check settings, config files, middleware)
• What framework protections exist?

Do NOT report issues based solely on pattern matching. Investigate first, then report only what you're confident is exploitable.

Confidence Levels

Do Not Flag

General Rules

• Test files (unless explicitly reviewing test security)
• Dead code, commented code, documentation strings
• Patterns using constants or server-controlled configuration
• Code paths that require prior authentication to reach (note the auth requirement instead)

Server-Controlled Values (NOT Attacker-Controlled)

These are configured by operators, not controlled by attackers:

SSRF Example - NOT a vulnerability:

# SAFE: URL comes from Django settings (server-controlled)
response = requests.get(f"{settings.SEER_AUTOFIX_URL}{path}")

SSRF Example - IS a vulnerability:

# VULNERABLE: URL comes from request (attacker-controlled)
response = requests.get(request.GET.get('url'))

Framework-Mitigated Patterns

Check language guides before flagging. Common false positives:

Only flag these when:

• Django: {{ var|safe }}, {% autoescape off %}, mark_safe(user_input)
• React: dangerouslySetInnerHTML={{__html: userInput}}
• Vue: v-html="userInput"
• ORM: .raw(), .extra(), RawSQL() with string interpolation

Review Process

1. Detect Context

What type of code am I reviewing?

2. Load Language Guide

Based on file extension or imports:

3. Load Infrastructure Guide (if applicable)

4. Research Before Flagging

For each potential issue, research the codebase to build confidence:

• Where does this value actually come from? Trace the data flow.
• Is it configured at deployment (settings, env vars) or from user input?
• Is there validation, sanitization, or allowlisting elsewhere?
• What framework protections apply?

Only report issues where you have HIGH confidence after understanding the broader context.

5. Verify Exploitability

For each potential finding, confirm:

Is the input attacker-controlled?

Does the framework mitigate this?

• Check language guide for auto-escaping, parameterization
• Check for middleware/decorators that sanitize

Is there validation upstream?

• Input validation before this code
• Sanitization libraries (DOMPurify, bleach, etc.)

6. Report HIGH Confidence Only

Skip theoretical issues. Report only what you've confirmed is exploitable after research.

Severity Classification

Quick Patterns Reference

Always Flag (Critical)

eval(user_input)           # Any language
exec(user_input)           # Any language
pickle.loads(user_data)    # Python
yaml.load(user_data)       # Python (not safe_load)
unserialize($user_data)    # PHP
deserialize(user_data)     # Java ObjectInputStream
shell=True + user_input    # Python subprocess
child_process.exec(user)   # Node.js

Always Flag (High)

innerHTML = userInput              # DOM XSS
dangerouslySetInnerHTML={user}     # React XSS
v-html="userInput"                 # Vue XSS
f"SELECT * FROM x WHERE {user}"    # SQL injection
`SELECT * FROM x WHERE ${user}`    # SQL injection
os.system(f"cmd {user_input}")     # Command injection

Always Flag (Secrets)

password = "hardcoded"
api_key = "sk-..."
AWS_SECRET_ACCESS_KEY = "..."
private_key = "-----BEGIN"

Check Context First (MUST Investigate Before Flagging)

# SSRF - ONLY if URL is from user input, NOT from settings/config
requests.get(request.GET['url'])     # FLAG: User-controlled URL
requests.get(settings.API_URL)       # SAFE: Server-controlled config
requests.get(f"{settings.BASE}/{x}") # CHECK: Is 'x' user input?

# Path traversal - ONLY if path is from user input
open(request.GET['file'])            # FLAG: User-controlled path
open(settings.LOG_PATH)              # SAFE: Server-controlled config
open(f"{BASE_DIR}/{filename}")       # CHECK: Is 'filename' user input?

# Open redirect - ONLY if URL is from user input
redirect(request.GET['next'])        # FLAG: User-controlled redirect
redirect(settings.LOGIN_URL)         # SAFE: Server-controlled config

# Weak crypto - ONLY if used for security purposes
hashlib.md5(file_content)            # SAFE: File checksums, caching
hashlib.md5(password)                # FLAG: Password hashing
random.random()                      # SAFE: Non-security uses (UI, sampling)
random.random() for token            # FLAG: Security tokens need secrets module

Output Format

## Security Review: [File/Component Name]

### Summary
- **Findings**: X (Y Critical, Z High, ...)
- **Risk Level**: Critical/High/Medium/Low
- **Confidence**: High/Mixed

### Findings

#### [VULN-001] [Vulnerability Type] (Severity)
- **Location**: `file.py:123`
- **Confidence**: High
- **Issue**: [What the vulnerability is]
- **Impact**: [What an attacker could do]
- **Evidence**:
  ```python
  [Vulnerable code snippet]

• Fix: [How to remediate]

Needs Verification

[VERIFY-001] [Potential Issue]

• Location: file.py:456
• Question: [What needs to be verified]

If no vulnerabilities found, state: "No high-confidence vulnerabilities identified."

---

## Reference Files

### Core Vulnerabilities (`references/`)
| File | Covers |
|------|--------|
| `injection.md` | SQL, NoSQL, OS command, LDAP, template injection |
| `xss.md` | Reflected, stored, DOM-based XSS |
| `authorization.md` | Authorization, IDOR, privilege escalation |
| `authentication.md` | Sessions, credentials, password storage |
| `cryptography.md` | Algorithms, key management, randomness |
| `deserialization.md` | Pickle, YAML, Java, PHP deserialization |
| `file-security.md` | Path traversal, uploads, XXE |
| `ssrf.md` | Server-side request forgery |
| `csrf.md` | Cross-site request forgery |
| `data-protection.md` | Secrets exposure, PII, logging |
| `api-security.md` | REST, GraphQL, mass assignment |
| `business-logic.md` | Race conditions, workflow bypass |
| `modern-threats.md` | Prototype pollution, LLM injection, WebSocket |
| `misconfiguration.md` | Headers, CORS, debug mode, defaults |
| `error-handling.md` | Fail-open, information disclosure |
| `supply-chain.md` | Dependencies, build security |
| `logging.md` | Audit failures, log injection |

### Language Guides (`languages/`)
- `python.md` - Django, Flask, FastAPI patterns
- `javascript.md` - Node, Express, React, Vue, Next.js

### Infrastructure (`infrastructure/`)
- `docker.md` - Container security