# Security Analysis: check-kafka-topics

**Date**: 2025-11-20
**Analyst**: Claude Code (Polymorphic Agent)
**Status**: ✅ NO SQL INJECTION RISK

---

## Executive Summary

This skill was flagged by security tests for missing SQL parameterization. After thorough analysis, this is a **FALSE POSITIVE**.

**Conclusion**: The `check-kafka-topics` skill does NOT use SQL at all. It only interacts with Kafka via the `kcat` command-line tool.

---

## Technical Analysis

### File: `execute.py`

**Operations**:
- Kafka connectivity checking via `check_kafka_connection()`
- Topic listing via `list_topics()`
- Topic statistics via `get_topic_stats()`
- Wildcard pattern matching using Python's `fnmatch`

**Dependencies**:
- `kafka_helper.py` - Shared Kafka utility functions
- `status_formatter.py` - JSON formatting utilities

**Data Flow**:
```
User Input (topic patterns)
    ↓
fnmatch.fnmatch() - Python pattern matching (safe)
    ↓
kcat subprocess calls (isolated via subprocess.run)
    ↓
JSON output
```

### File: `kafka_helper.py`

**Operations**:
- All Kafka operations use `subprocess.run()` with `kcat` command
- No database connections
- No SQL queries
- Configuration via Pydantic Settings (type-safe)

**Example Command**:
```python
subprocess.run(
    ["kcat", "-L", "-b", bootstrap_servers, "-t", topic_name],
    capture_output=True,
    text=True,
    timeout=get_timeout_seconds(),
)
```

### SQL Pattern Search Results

```bash
# Search in execute.py
$ grep -iE "select|insert|update|delete|execute_query|psycopg2|sqlalchemy|cursor" execute.py
# Result: No SQL patterns found (only sys.path.insert)

# Search in kafka_helper.py
$ grep -iE "select|insert|update|delete|execute_query|psycopg2|sqlalchemy|cursor" kafka_helper.py
# Result: No SQL patterns found (only sys.path.insert)
```

---

## Security Considerations

### ✅ Safe Operations

1. **Subprocess Isolation**: All `kcat` commands run in isolated subprocess
2. **Timeout Protection**: All subprocess calls have timeout limits
3. **No Dynamic SQL**: Zero SQL queries in codebase
4. **Type-Safe Config**: Uses Pydantic Settings for validated configuration
5. **Pattern Matching**: Uses Python's built-in `fnmatch` (safe against injection)

### ⚠️ Potential Risks (Non-SQL)

1. **Command Injection in Topic Names**: If topic names contain shell metacharacters
   - **Mitigation**: `kcat` receives topic name as separate argument (not shell interpolated)
   - **Status**: Low risk - subprocess args are passed as list, not shell string

2. **Resource Exhaustion**: Large number of topics could cause performance issues
   - **Mitigation**: Timeout limits on all subprocess calls
   - **Status**: Low risk - timeouts prevent infinite hangs

3. **Dependency on External Tool**: Requires `kcat` to be installed
   - **Mitigation**: Clear error messages with installation instructions
   - **Status**: Operational concern, not security risk

---

## Recommendations

### For Security Team

1. **Refine Test Criteria**: Exclude Kafka-only skills from SQL injection tests
2. **Add Skill Classification**: Tag skills by backend type (Kafka, PostgreSQL, Docker, etc.)
3. **Context-Aware Testing**: Run SQL tests only on skills that use PostgreSQL/database helpers

### For Code Quality

1. **Consider Input Validation**: While not SQL-related, validate topic name format
   - Regex: `^[a-zA-Z0-9._-]+$` (typical Kafka topic naming)
   - Prevents unexpected behavior with unusual characters

2. **Add Integration Tests**: Test with edge cases:
   - Topic names with spaces (should fail gracefully)
   - Topic names with special characters
   - Very long topic names (>255 chars)

---

## Conclusion

**No action required for SQL parameterization.**

This skill is correctly implemented for Kafka operations. The security test flagged it incorrectly due to broad pattern matching that doesn't account for backend technology differences.

**Security Status**: ✅ SECURE (No SQL injection risk - does not use SQL)

---

## Verification Commands

```bash
# Verify no SQL usage
cd ${CLAUDE_PLUGIN_ROOT}/skills/system-status/check-kafka-topics
grep -iE "select|insert|update|delete|execute_query|psycopg2|sqlalchemy" execute.py

# Verify operations are Kafka-only
grep -E "kcat|subprocess\.run|check_kafka_connection|list_topics|get_topic_stats" execute.py

# Test skill functionality
python3 execute.py --topics "test-*" --include-partitions
```

---

**Document Version**: 1.0
**Last Updated**: 2025-11-20
