# Security Guidelines

This document outlines security practices and procedures for the Tumor Detection Segmentation project.

## Table of Contents
- [Security Scanning](#security-scanning)
- [Secrets Management](#secrets-management)
- [Secure Development Practices](#secure-development-practices)
- [Vulnerability Management](#vulnerability-management)
- [Incident Response](#incident-response)

## Security Scanning

### Automated Security Scans

The project uses automated security scanning in CI/CD:

#### Bandit (Python Security Linter)
- Scans Python code for common security issues
- Runs on every push and pull request
- Fails build on high-severity findings
- Results uploaded as artifacts

#### Trivy (Container Vulnerability Scanner)
- Scans Docker images for OS and library vulnerabilities
- Runs on container builds
- SARIF reports uploaded to GitHub Security tab
- Configurable severity thresholds

#### GitHub Secret Scanning
- Automatically detects exposed secrets
- Scans commits and pull requests
- Alerts maintainers of potential leaks
- Supports custom patterns

### Running Security Scans Locally

```bash
# Run Bandit
pip install bandit
bandit -r src/ -f json

# Run Trivy on Docker image
docker run --rm -v /var/run/docker.sock:/var/run/docker.sock \
  aquasecurity/trivy:latest image tumor-detection:latest

# Check for secrets
pip install detect-secrets
detect-secrets scan --all-files
```

## Secrets Management

### Environment Variables

#### Development
- Store secrets in `docker/.env` (gitignored)
- Never commit `.env` files
- Use different files for different environments:
  - `docker/.env` - Development
  - `docker/.env.staging` - Staging
  - `docker/.env.prod` - Production

#### Production
- Use Docker secrets or external secret managers
- Never store secrets in environment variables directly
- Rotate secrets regularly

### GitHub Secrets

For CI/CD pipelines:

```yaml
# In .github/workflows/*.yml
- name: Deploy
  env:
    DATABASE_URL: ${{ secrets.DATABASE_URL }}
    API_KEY: ${{ secrets.API_KEY }}
  run: docker-compose up -d
```

### External Secret Managers

#### AWS Secrets Manager
```python
import boto3

client = boto3.client('secretsmanager')
response = client.get_secret_value(SecretId='my-secret')
secret = response['SecretString']
```

#### HashiCorp Vault
```python
import hvac

client = hvac.Client(url='https://vault.example.com')
client.auth_github('your-token')
secret = client.read('secret/my-app')['data']
```

#### Azure Key Vault
```python
from azure.keyvault.secrets import SecretClient
from azure.identity import DefaultAzureCredential

credential = DefaultAzureCredential()
client = SecretClient(vault_url="https://myvault.vault.azure.net/", credential=credential)
secret = client.get_secret('my-secret')
```

## Secure Development Practices

### Code Security

#### Input Validation
```python
from pydantic import BaseModel, validator

class UserInput(BaseModel):
    username: str
    email: str

    @validator('username')
    def username_must_be_valid(cls, v):
        if not v.isalnum():
            raise ValueError('Username must be alphanumeric')
        return v
```

#### SQL Injection Prevention
```python
# Bad - vulnerable to SQL injection
query = f"SELECT * FROM users WHERE id = {user_id}"

# Good - use parameterized queries
cursor.execute("SELECT * FROM users WHERE id = %s", (user_id,))
```

#### XSS Prevention
```python
from html import escape

# Escape user input in HTML
safe_html = f"<div>{escape(user_input)}</div>"
```

### Dependency Security

#### Regular Updates
```bash
# Update dependencies
pip install --upgrade -r requirements.txt

# Check for vulnerabilities
pip install safety
safety check
```

#### Dependency Scanning
- Use `pip-audit` for Python dependencies
- Review dependency licenses
- Pin versions in production
- Monitor for security advisories

### Container Security

#### Dockerfile Best Practices
```dockerfile
# Use specific base images
FROM python:3.11-slim

# Create non-root user
RUN useradd --create-home --shell /bin/bash app
USER app

# Minimize layers
RUN apt-get update && apt-get install -y \
    package1 \
    package2 \
    && rm -rf /var/lib/apt/lists/*
```

#### Image Scanning
```bash
# Scan image before deployment
trivy image --exit-code 1 --severity HIGH,CRITICAL my-image:latest
```

## Vulnerability Management

### Process
1. **Detection**: Automated scans identify vulnerabilities
2. **Assessment**: Evaluate impact and exploitability
3. **Prioritization**: Rank by severity and business impact
4. **Remediation**: Fix or mitigate vulnerabilities
5. **Verification**: Confirm fixes work
6. **Monitoring**: Track vulnerability status

### Severity Levels
- **Critical**: Immediate action required
- **High**: Fix within 7 days
- **Medium**: Fix within 30 days
- **Low**: Fix when convenient

### Reporting
- Use GitHub Security Advisories for public vulnerabilities
- Internal tracking for non-public issues
- Regular security reports to stakeholders

## Incident Response

### Response Plan
1. **Detection**: Monitor for security events
2. **Assessment**: Evaluate incident scope and impact
3. **Containment**: Isolate affected systems
4. **Eradication**: Remove threat vectors
5. **Recovery**: Restore systems and data
6. **Lessons Learned**: Document and improve

### Communication
- Internal: Notify security team immediately
- External: Follow legal and regulatory requirements
- Users: Transparent communication when data is affected

### Tools and Monitoring
- Log analysis for suspicious activity
- Intrusion detection systems
- Regular security audits
- Penetration testing

## Compliance

### Standards
- OWASP Top 10
- NIST Cybersecurity Framework
- GDPR for data protection
- HIPAA for healthcare data

### Regular Activities
- Quarterly security assessments
- Annual penetration testing
- Regular dependency updates
- Security training for developers

## Contact

For security concerns:
- **Email**: security@tumor-detection.com
- **GitHub**: Create security advisory
- **Response Time**: Critical issues within 24 hours

## Resources

- [OWASP Cheat Sheet](https://cheatsheetseries.owasp.org/)
- [NIST Cybersecurity Framework](https://www.nist.gov/cyberframework)
- [SANS Security Policy Templates](https://www.sans.org/information-security-policy/)
- [GitHub Security Best Practices](https://docs.github.com/en/code-security)
