skills-firewall

Security firewall for skills that automatically blocks and filters malicious or potentially harmful skills. Use when: (1) Scanning skills for security threats. (2) Checking if a skill is safe to use. (3) Filtering multiple skills based on security rules. (4) Generating security reports for skills. (5) Managing allowed/blocked skill lists. (6) Reviewing skills before installation or execution.

A security firewall that automatically blocks and filters malicious or potentially harmful skills by analyzing code patterns, detecting security threats, and enforcing security policies.

Quick Start

Scan a Single Skill

bash

python scripts/scan_skill.py /path/to/skill

Check Firewall Decision

bash

python scripts/firewall_check.py /path/to/skill

Generate Security Report

bash

python scripts/generate_report.py /path/to/skills --format text

Core Workflows

1. Security Scanning

Scan skills for potential security threats:

bash

# Scan single skill
python scripts/scan_skill.py ./my-skill

# Scan all skills in directory
python scripts/scan_skill.py ./skills

# JSON output for automation
python scripts/scan_skill.py ./my-skill --json

Threat Levels:

• SAFE - No security concerns
• LOW - Minor concerns, generally safe
• MEDIUM - Moderate concerns, review recommended
• HIGH - Significant risks, blocking recommended
• CRITICAL - Severe threats, must block

2. Firewall Filtering

Check and filter skills based on security rules:

bash

# Check single skill
python scripts/firewall_check.py ./my-skill

# Filter all skills
python scripts/firewall_check.py ./skills

# Add to allowed list
python scripts/firewall_check.py ./my-skill --allow

# Add to blocked list
python scripts/firewall_check.py ./my-skill --block

Actions:

• allow - Skill passes firewall
• warn - Skill has warnings but allowed
• block - Skill is blocked
• quarantine - Skill isolated for review

3. Security Reports

Generate comprehensive security reports:

bash

# Text report
python scripts/generate_report.py ./skills

# JSON report
python scripts/generate_report.py ./skills --format json

# HTML report
python scripts/generate_report.py ./skills --format html --output report.html

Detection Categories

The firewall detects threats in these categories:

Category	Examples	Severity
Code Injection	eval(), exec(), import()	HIGH
Command Execution	subprocess shell=True, os.system()	HIGH
Credential Exposure	Hardcoded passwords, API keys	CRITICAL
Network Communication	HTTP requests, socket connections	MEDIUM
File Operations	File deletion, modification	MEDIUM
Deserialization	pickle.loads, unsafe yaml.load	HIGH
Privilege Escalation	sudo, chmod 777	HIGH
Obfuscation	Base64 decoding, encoding	LOW

Configuration

Export/Import Config

bash

# Export current config
python scripts/firewall_check.py ./skills --export-config firewall.yaml

# Use custom config
python scripts/firewall_check.py ./skills --config firewall.yaml

Config File Format

yaml

default_action: warn
allowed_skills:
  - skill-creator
  - weather
blocked_skills:
  - malicious-skill
quarantine_dir: ./quarantine
rules:
  - name: block_eval
    description: Block eval() usage
    patterns:
      - "eval("
    action: block
    enabled: true

Reference Documentation

• Malicious Patterns: See malicious_patterns.md for detailed pattern catalog
• Security Rules: See security_rules.md for rule definitions and configuration

Programmatic Usage

python

from scan_skill import scan_skill, ThreatLevel
from firewall_check import SkillsFirewall, ActionType

# Scan a skill
result = scan_skill("/path/to/skill")
print(f"Threat Level: {result.threat_level}")
print(f"Is Safe: {result.is_safe}")

# Use firewall
firewall = SkillsFirewall()
decision = firewall.check_skill("/path/to/skill")
print(f"Action: {decision.action}")
print(f"Reason: {decision.reason}")

# Manage lists
firewall.add_allowed_skill("trusted-skill")
firewall.add_blocked_skill("malicious-skill")

# Create custom rule
firewall.create_rule(
    name="block_custom_pattern",
    description="Block custom dangerous pattern",
    patterns=["dangerous_function("],
    action=ActionType.BLOCK
)

Best Practices

1. Scan Before Use: Always scan new skills before installation
2. Review Warnings: Investigate warning-level findings
3. Update Rules: Keep detection patterns current
4. Document Exceptions: Record why skills are allowed/blocked
5. Regular Audits: Run periodic security scans
6. Use Reports: Generate reports for compliance and review