Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/nickcrew/claude-cortex --skill owasp-top-10- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads owasp-top-10 automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
OWASP Top 10 Security Vulnerabilities
Expert guidance for identifying, preventing, and remediating the most critical web application security risks based on OWASP Top 10 2021.
When to Use This Skill
- Conducting security audits and code reviews
- Implementing secure coding practices in new features
- Reviewing authentication and authorization systems
- Assessing input validation and sanitization
- Evaluating third-party dependencies for vulnerabilities
- Designing security controls and defense-in-depth strategies
- Preparing for security certifications or compliance audits
- Investigating security incidents or suspicious behavior
OWASP Top 10 2021 Overview
Ranked by Risk Severity:
- A01 - Broken Access Control (↑ from #5)
- A02 - Cryptographic Failures (formerly Sensitive Data Exposure)
- A03 - Injection (↓ from #1)
- A04 - Insecure Design (NEW)
- A05 - Security Misconfiguration
- A06 - Vulnerable and Outdated Components
- A07 - Identification and Authentication Failures
- A08 - Software and Data Integrity Failures (NEW)
- A09 - Security Logging and Monitoring Failures
- A10 - Server-Side Request Forgery (SSRF) (NEW)
Quick Reference
Load detailed guidance for each vulnerability:
| Vulnerability | Reference File |
|---|---|
| Broken Access Control | skills/owasp-top-10/references/broken-access-control.md |
| Cryptographic Failures | skills/owasp-top-10/references/cryptographic-failures.md |
| Injection | skills/owasp-top-10/references/injection.md |
| Insecure Design | skills/owasp-top-10/references/insecure-design.md |
| Security Misconfiguration | skills/owasp-top-10/references/security-misconfiguration.md |
| Vulnerable Components | skills/owasp-top-10/references/vulnerable-components.md |
| Authentication Failures | skills/owasp-top-10/references/authentication-failures.md |
| Integrity Failures | skills/owasp-top-10/references/integrity-failures.md |
| Logging & Monitoring | skills/owasp-top-10/references/logging-monitoring.md |
| SSRF | skills/owasp-top-10/references/ssrf.md |
| Prevention Strategies | skills/owasp-top-10/references/prevention-strategies.md |
| Assessment Workflow | skills/owasp-top-10/references/assessment-workflow.md |
Security Audit Workflow
- Identify Scope: Determine application components and attack surface
- Select Vulnerabilities: Choose relevant OWASP categories based on features
- Load Reference: Read appropriate reference file(s) for detailed patterns
- Analyze Code: Review code against vulnerable and secure patterns
- Document Findings: Record vulnerabilities with severity and remediation
- Verify Fixes: Test that remediations properly address issues
- Test Security: Run automated security testing (SAST, DAST, SCA)
Core Security Principles
Defense in Depth
- Layer security controls at network, application, data, and monitoring levels
- Ensure failure of one control doesn't compromise entire system
Secure by Default
- Deny all access by default, explicitly grant permissions
- Fail securely (errors don't expose sensitive information)
- Minimize attack surface (disable unused features)
- Apply least privilege to all accounts and services
Input Validation
- Validate type, length, format, and allowed values
- Use allow-lists over deny-lists
- Sanitize for specific context (SQL, HTML, shell, etc.)
- Never trust client input
Common Mistakes
- Trusting User Input: Always validate and sanitize all user-supplied data
- Rolling Your Own Crypto: Use established libraries (bcrypt, AES-256)
- Exposing Errors: Log detailed errors internally, show generic messages to users
- Missing Authorization: Check permissions on every request, not just UI
- Weak Session Management: Use secure, httpOnly, sameSite cookies with HTTPS
- Ignoring Dependencies: Regularly audit and update third-party libraries
- No Logging: Log security events for detection and incident response
- Default Configurations: Harden all systems, disable defaults
Security Testing Tools
SAST (Static): SonarQube, Semgrep, ESLint security plugins DAST (Dynamic): OWASP ZAP, Burp Suite SCA (Dependencies): npm audit, Snyk, Dependabot Secrets Scanning: GitGuardian, TruffleHog Penetration Testing: Metasploit, Kali Linux tools
Resources
- OWASP Top 10 2021: https://owasp.org/Top10/
- OWASP Cheat Sheets: https://cheatsheetseries.owasp.org/
- OWASP ASVS: Application Security Verification Standard
- CWE Top 25: Common Weakness Enumeration
- NIST Cybersecurity Framework: https://www.nist.gov/cyberframework
- CVE Database: https://cve.mitre.org/
- Snyk Vulnerability DB: https://snyk.io/vuln/
FAQ
What does the owasp-top-10 skill do?
OWASP Top 10 security vulnerabilities with detection and remediation patterns. Use when conducting security audits, implementing secure coding practices, or reviewing code for common security vulnerabilities.
How do I install owasp-top-10?
Run npx skills add https://github.com/nickcrew/claude-cortex --skill owasp-top-10 in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/owasp-top-10/ (personal) or .claude/skills/owasp-top-10/ (project).
Which AI agents can use owasp-top-10?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is owasp-top-10 safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains owasp-top-10?
It is published by nickcrew in nickcrew/claude-cortex. It has 758 recorded installs.
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