Vulnhunter Skill for Cursor

- CORS: Access-Control-Allow-Origin: *
- Debug modes enabled in production
- Default credentials or API keys
- Permissive file permissions (777, 666)
- SSL/TLS verification disabled
- Insecure deserialization settings

// Dangerous: No bounds checking
strcpy(), strcat(), sprintf(), gets()
memcpy() without size validation

// Safer alternatives
strncpy(), strncat(), snprintf(), fgets()
memcpy_s() with explicit size

- ECB mode encryption
- MD5/SHA1 for security purposes
- Hardcoded IVs or salts
- Custom crypto implementations
- Random without CSPRNG (Math.random for tokens)

- Race conditions in file operations
- Time-of-check to time-of-use (TOCTOU)
- Double-checked locking anti-patterns
- Non-atomic increment/decrement operations

// Dangerous patterns
eval(), new Function(), setTimeout(string)
innerHTML, outerHTML, document.write()
Object.assign() for deep clone (shallow only!)
== instead of === (type coercion)

# Dangerous patterns
pickle.loads(untrusted)  # RCE vector
yaml.load(untrusted)     # Use safe_load
exec(), eval()
os.system(), subprocess with shell=True

// Patterns requiring extra scrutiny
unsafe { }
.unwrap() in production code
mem::transmute()
raw pointer dereference

// High-risk patterns
tx.origin for authentication  // Phishing vulnerable
delegatecall to untrusted     // Storage collision
selfdestruct                  // Permanent destruction
block.timestamp for randomness // Miner manipulable

Original bug: User input flows to SQL query without sanitization
Pattern: [user_input] -> [sink_function] without [validation_function]

Search for:
- Direct database calls with string concatenation
- ORM raw query methods with user parameters
- Similar data flows in adjacent modules

Original bug: Endpoint missing auth middleware
Pattern: Route definition without auth decorator/middleware

Search for:
- Routes defined after the vulnerable one
- Similar API patterns in other modules
- Admin/internal endpoints

Original bug: Check-then-act without atomicity
Pattern: if (check_condition()) { act_on_condition() }

Search for:
- File existence checks followed by file operations
- Permission checks followed by privileged actions
- Balance checks followed by transfers

# Find potential SQL injection
grep -rn "execute.*%s" --include="*.py"
grep -rn "query.*\+" --include="*.js"

# Find dangerous deserialize
grep -rn "pickle.loads\|yaml.load\|eval(" --include="*.py"

# Find command injection vectors
grep -rn "os.system\|subprocess.*shell=True" --include="*.py"

## Variant Analysis Report

### Original Finding
- **ID**: FINDING-001
- **Severity**: High
- **Root Cause**: [Description]
- **Affected File**: path/to/file.ext:line

### Pattern Extracted
[Code pattern or regex]

### Variants Discovered

| # | Location | Severity | Status | Notes |
|---|----------|----------|--------|-------|
| 1 | file.ext:42 | High | Confirmed | Same root cause |
| 2 | other.ext:100 | Medium | Suspected | Needs validation |

### Recommendations
[Systematic fix approach]

# Example: Detect SQL injection in Python
rules:
  - id: sql-injection-format
    patterns:
      - pattern: $CURSOR.execute($QUERY % ...)
    message: "Potential SQL injection via string formatting"
    severity: ERROR
    languages: [python]

// Find tainted data flowing to dangerous sinks
import python
import semmle.python.dataflow.TaintTracking

from DataFlow::PathNode source, DataFlow::PathNode sink
where TaintTracking::localTaint(source.getNode(), sink.getNode())
  and sink.getNode().asExpr().(Call).getTarget().getName() = "execute"
select sink, source, sink, "Tainted input reaches SQL execution"

vulnhunter/
├── SKILL.md                          # This file
├── resources/
│   ├── sharp-edges-catalog.md        # Categorized dangerous patterns
│   └── variant-patterns.md           # Vulnerability pattern templates
├── examples/
│   ├── smart-contracts/              # Solidity/blockchain examples
│   ├── web-apps/                     # Web application examples
│   └── native-code/                  # C/C++/Rust examples
├── templates/
│   └── variant-report.md             # Analysis report template
└── docs/
    └── methodology.md                # Detailed methodology guide