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Security audit

API Security Best Practices

Security checks for vulnerabilities and agentic risk

Overview

This is a documentation-only API security skill, but its JWT example includes unsafe refresh-token storage guidance that could weaken an application if copied as written.

Review and correct the JWT refresh-token section before relying on this skill. It appears safe to install from an agent-behavior perspective, but developers should not copy the refresh-token storage pattern as written; store only token hashes, rotate refresh tokens, support revocation, and handle browser tokens with secure cookies where appropriate.

Vulnerability Patterns
  • Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
Findings (1)

T09 · Insecure Skill Coding Practices

Warning
Location
SKILL.md:107
Finding

Refresh Tokens Stored in Plaintext

Content
View full analysis
Remediation
View remediation
Vulnerability Patterns
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
Findings (2)

Credential Access

High
Category
Privilege Escalation
Confidence
70% confidence
Finding

Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Content

Scanner excerpt · SKILL.md (reported line 141)May include surrounding context.

md
const token = authHeader && authHeader.split(' ')[1]; // Bearer TOKEN
  
  if (!token) {
    return res.status(401).json({ error: 'Access token required' });
  }
  
  jwt.verify(

Credential Access

High
Category
Privilege Escalation
Confidence
70% confidence
Finding

Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.

Content

Scanner excerpt · SKILL.md (reported line 374)May include surrounding context.

md
- **Use Parameterized Queries** - Prevent SQL injection
- **Implement Rate Limiting** - Protect against brute force and DDoS
- **Hash Passwords** - Use bcrypt with salt rounds >= 10
- **Use Short-Lived Tokens** - JWT access tokens should expire quickly
- **Implement CORS Properly** - Only allow trusted origins
- **Log Security Events** - Monitor for suspicious activity
- **Use Security Headers** - Implement Helmet.js

Static analysis

No suspicious patterns detected.