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

| Level | Criteria | Action | |-------|----------|--------| | HIGH | Vulnerable pattern + attacker-controlled input confirmed | Report with severity | | MEDIUM | Vulnerable pattern, input source unclear | Note as "Needs verification" | | LOW | Theoretical, best practice, defense-in-depth | Do not report |

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:

| Source | Example | Why It's Safe | |--------|---------|---------------| | Django settings | settings.API_URL, settings.ALLOWED_HOSTS | Set via config/env at deployment | | Environment variables | os.environ.get('DATABASE_URL') | Deployment configuration | | Config files | config.yaml, app.config['KEY'] | Server-side files | | Framework constants | django.conf.settings.* | Not user-modifiable | | Hardcoded values | BASE_URL = "https://api.internal" | Compile-time constants |

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:

| Pattern | Why It's Usually Safe | |---------|----------------------| | Django {{ variable }} | Auto-escaped by default | | React {variable} | Auto-escaped by default | | Vue {{ variable }} | Auto-escaped by default | | User.objects.filter(id=input) | ORM parameterizes queries | | cursor.execute("...%s", (input,)) | Parameterized query | | innerHTML = "Loading..." | Constant string, no user input |

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?

| Code Type | Load These References | |-----------|----------------------| | API endpoints, routes | authorization.md, authentication.md, injection.md | | Frontend, templates | xss.md, csrf.md | | File handling, uploads | file-security.md | | Crypto, secrets, tokens | cryptography.md, data-protection.md | | Data serialization | deserialization.md | | External requests | ssrf.md | | Business workflows | business-logic.md | | GraphQL, REST design | api-security.md | | Config, headers, CORS | misconfiguration.md | | CI/CD, dependencies | supply-chain.md | | Error handling | error-handling.md | | Audit, logging | logging.md |

2. Load Language Guide

Based on file extension or imports:

| Indicators | Guide | |------------|-------| | .py, django, flask, fastapi | languages/python.md | | .js, .ts, express, react, vue, next | languages/javascript.md | | .go, go.mod | languages/go.md | | .rs, Cargo.toml | languages/rust.md | | .java, spring, @Controller | languages/java.md |

3. Load Infrastructure Guide (if applicable)

| File Type | Guide | |-----------|-------| | Dockerfile, .dockerignore | infrastructure/docker.md | | K8s manifests, Helm charts | infrastructure/kubernetes.md | | .tf, Terraform | infrastructure/terraform.md | | GitHub Actions, .gitlab-ci.yml | infrastructure/ci-cd.md | | AWS/GCP/Azure configs, IAM | infrastructure/cloud.md |

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?

| Attacker-Controlled (Investigate) | Server-Controlled (Usually Safe) | |-----------------------------------|----------------------------------| | request.GET, request.POST, request.args | settings.X, app.config['X'] | | request.json, request.data, request.body | os.environ.get('X') | | request.headers (most headers) | Hardcoded constants | | request.cookies (unsigned) | Internal service URLs from config | | URL path segments: /users// | Database content from admin/system | | File uploads (content and names) | Signed session data | | Database content from other users | Framework settings | | WebSocket messages | |

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.

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Severity Classification

| Severity | Impact | Examples | |----------|--------|----------| | Critical | Direct exploit, severe impact, no auth required | RCE, SQL injection to data, auth bypass, hardcoded secrets | | High | Exploitable with conditions, significant impact | Stored XSS, SSRF to metadata, IDOR to sensitive data | | Medium | Specific conditions required, moderate impact | Reflected XSS, CSRF on state-changing actions, path traversal | | Low | Defense-in-depth, minimal direct impact | Missing headers, verbose errors, weak algorithms in non-critical context |

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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

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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
• go.md - Go-specific security patterns
• rust.md - Rust unsafe blocks, FFI security
• java.md - Spring, Java EE patterns

Infrastructure (infrastructure/)

• docker.md - Container security
• kubernetes.md - K8s RBAC, secrets, policies
• terraform.md - IaC security
• ci-cd.md - Pipeline security
• cloud.md - AWS/GCP/Azure security

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: getsentry
• Source: getsentry/skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.