Files
claude-skills-reference/engineering/skill-tester/scripts/security_scorer.py
xingzihai 2f92a1dfcb feat(skill-tester): add Security dimension to quality scoring system
- Add SecurityScorer module (605 lines) with comprehensive security assessment
- Add 4 security scoring components:
  - Sensitive data exposure prevention (hardcoded credentials detection)
  - Safe file operations (path traversal prevention)
  - Command injection prevention (shell=True, eval, exec detection)
  - Input validation quality (argparse, error handling, type checking)
- Add 53 unit tests with 850 lines of test code
- Update quality_scorer.py to integrate Security dimension (20% weight)
- Rebalance all dimensions from 25% to 20% (5 dimensions total)
- Update tier requirements:
  - POWERFUL: Security ≥70
  - STANDARD: Security ≥50
  - BASIC: Security ≥40
- Update documentation (quality-scoring-rubric.md, tier-requirements-matrix.md)
- Version bump to 2.0.0

This addresses the feedback from PR #420 by providing a focused, well-tested
implementation of the Security dimension without bundling other changes.
2026-03-26 13:25:27 +00:00

606 lines
23 KiB
Python

#!/usr/bin/env python3
"""
Security Scorer - Security dimension scoring module
This module provides comprehensive security assessment for Python scripts,
evaluating sensitive data exposure, safe file operations, command injection
prevention, and input validation quality.
Author: Claude Skills Engineering Team
Version: 2.0.0
"""
import re
from pathlib import Path
from typing import Dict, List, Tuple, Optional, Any
# =============================================================================
# CONSTANTS - Scoring thresholds and weights
# =============================================================================
# Maximum score per component (25 points each, 4 components = 100 total)
MAX_COMPONENT_SCORE: int = 25
# Minimum score floor (never go below 0)
MIN_SCORE: int = 0
# Security score thresholds for tier recommendations
SECURITY_SCORE_POWERFUL_TIER: int = 70 # Required for POWERFUL tier
SECURITY_SCORE_STANDARD_TIER: int = 50 # Required for STANDARD tier
# Scoring modifiers (magic numbers replaced with named constants)
BASE_SCORE_SENSITIVE_DATA: int = 25 # Start with full points
BASE_SCORE_FILE_OPS: int = 15 # Base score for file operations
BASE_SCORE_COMMAND_INJECTION: int = 25 # Start with full points
BASE_SCORE_INPUT_VALIDATION: int = 10 # Base score for input validation
# Penalty amounts (negative scoring)
CRITICAL_VULNERABILITY_PENALTY: int = -25 # Critical issues (hardcoded passwords, etc.)
HIGH_SEVERITY_PENALTY: int = -10 # High severity issues
MEDIUM_SEVERITY_PENALTY: int = -5 # Medium severity issues
LOW_SEVERITY_PENALTY: int = -2 # Low severity issues
# Bonus amounts (positive scoring)
SAFE_PATTERN_BONUS: int = 2 # Bonus for using safe patterns
GOOD_PRACTICE_BONUS: int = 3 # Bonus for good security practices
# =============================================================================
# PRE-COMPILED REGEX PATTERNS - Sensitive Data Detection
# =============================================================================
# Hardcoded credentials patterns (CRITICAL severity)
PATTERN_HARDCODED_PASSWORD = re.compile(
r'password\s*=\s*["\'][^"\']{4,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_API_KEY = re.compile(
r'api_key\s*=\s*["\'][^"\']{8,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_SECRET = re.compile(
r'secret\s*=\s*["\'][^"\']{4,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_TOKEN = re.compile(
r'token\s*=\s*["\'][^"\']{8,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_PRIVATE_KEY = re.compile(
r'private_key\s*=\s*["\'][^"\']{20,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_AWS_KEY = re.compile(
r'aws_access_key\s*=\s*["\'][^"\']{16,}["\']',
re.IGNORECASE
)
PATTERN_HARDCODED_AWS_SECRET = re.compile(
r'aws_secret\s*=\s*["\'][^"\']{20,}["\']',
re.IGNORECASE
)
# Multi-line string patterns (CRITICAL severity)
PATTERN_MULTILINE_STRING = re.compile(
r'["\']{3}[^"\']*?(?:password|api_key|secret|token|private_key)[^"\']*?["\']{3}',
re.IGNORECASE | re.DOTALL
)
# F-string patterns (HIGH severity)
PATTERN_FSTRING_SENSITIVE = re.compile(
r'f["\'].*?(?:password|api_key|secret|token)\s*=',
re.IGNORECASE
)
# Base64 encoded secrets (MEDIUM severity)
PATTERN_BASE64_SECRET = re.compile(
r'(?:base64|b64encode|b64decode)\s*\([^)]*(?:password|api_key|secret|token)',
re.IGNORECASE
)
# JWT tokens (HIGH severity)
PATTERN_JWT_TOKEN = re.compile(
r'eyJ[a-zA-Z0-9_-]*\.eyJ[a-zA-Z0-9_-]*\.[a-zA-Z0-9_-]*'
)
# Connection strings (HIGH severity)
PATTERN_CONNECTION_STRING = re.compile(
r'(?:connection_string|conn_string|database_url)\s*=\s*["\'][^"\']*(?:password|pwd|passwd)[^"\']*["\']',
re.IGNORECASE
)
# Safe credential patterns (environment variables are OK)
PATTERN_SAFE_ENV_VAR = re.compile(
r'os\.(?:getenv|environ)\s*\(\s*["\'][^"\']+["\']',
re.IGNORECASE
)
# =============================================================================
# PRE-COMPILED REGEX PATTERNS - Path Traversal Detection
# =============================================================================
# Basic path traversal patterns
PATTERN_PATH_TRAVERSAL_BASIC = re.compile(r'\.\.\/')
PATTERN_PATH_TRAVERSAL_WINDOWS = re.compile(r'\.\.\\')
# URL encoded path traversal (MEDIUM severity)
PATTERN_PATH_TRAVERSAL_URL_ENCODED = re.compile(
r'%2e%2e%2f|%252e%252e%252f|\.\.%2f',
re.IGNORECASE
)
# Unicode encoded path traversal (MEDIUM severity)
PATTERN_PATH_TRAVERSAL_UNICODE = re.compile(
r'\\u002e\\u002e|\\uff0e\\uff0e|\u002e\u002e\/',
re.IGNORECASE
)
# Null byte injection (HIGH severity)
PATTERN_NULL_BYTE = re.compile(r'%00|\\x00|\0')
# Risky file operation patterns
PATTERN_PATH_CONCAT = re.compile(
r'open\s*\(\s*[^)]*\+',
re.IGNORECASE
)
PATTERN_USER_INPUT_PATH = re.compile(
r'\.join\s*\(\s*[^)]*input|os\.path\.join\s*\([^)]*request',
re.IGNORECASE
)
# Safe file operation patterns
PATTERN_SAFE_BASENAME = re.compile(r'os\.path\.basename', re.IGNORECASE)
PATTERN_SAFE_PATHLIB = re.compile(r'pathlib\.Path\s*\(', re.IGNORECASE)
PATTERN_PATH_VALIDATION = re.compile(r'validate.*path', re.IGNORECASE)
PATTERN_PATH_RESOLVE = re.compile(r'\.resolve\s*\(', re.IGNORECASE)
# =============================================================================
# PRE-COMPILED REGEX PATTERNS - Command Injection Detection
# =============================================================================
# Dangerous patterns (CRITICAL severity)
PATTERN_OS_SYSTEM = re.compile(r'os\.system\s*\(')
PATTERN_OS_POPEN = re.compile(r'os\.popen\s*\(')
PATTERN_EVAL = re.compile(r'eval\s*\(')
PATTERN_EXEC = re.compile(r'exec\s*\(')
# Subprocess with shell=True (HIGH severity)
PATTERN_SUBPROCESS_SHELL_TRUE = re.compile(
r'subprocess\.(?:call|run|Popen|check_output)\s*\([^)]*shell\s*=\s*True',
re.IGNORECASE
)
# Asyncio subprocess shell (HIGH severity)
PATTERN_ASYNCIO_SHELL = re.compile(
r'asyncio\.create_subprocess_shell\s*\(',
re.IGNORECASE
)
# Pexpect spawn (HIGH severity)
PATTERN_PEXPECT_SPAWN = re.compile(r'pexpect\.spawn\s*\(', re.IGNORECASE)
# Safe subprocess patterns
PATTERN_SAFE_SUBPROCESS = re.compile(
r'subprocess\.(?:run|call|Popen)\s*\([^)]*shell\s*=\s*False',
re.IGNORECASE
)
PATTERN_SHLEX_QUOTE = re.compile(r'shlex\.quote', re.IGNORECASE)
PATTERN_SHLEX_SPLIT = re.compile(r'shlex\.split', re.IGNORECASE)
# =============================================================================
# PRE-COMPILED REGEX PATTERNS - Input Validation Detection
# =============================================================================
# Good validation patterns
PATTERN_ARGPARSE = re.compile(r'argparse')
PATTERN_TRY_EXCEPT = re.compile(r'try\s*:[\s\S]*?except\s+\w*Error')
PATTERN_INPUT_CHECK = re.compile(r'if\s+not\s+\w+\s*:')
PATTERN_ISINSTANCE = re.compile(r'isinstance\s*\(')
PATTERN_ISDIGIT = re.compile(r'\.isdigit\s*\(\)')
PATTERN_REGEX_VALIDATION = re.compile(r're\.(?:match|search|fullmatch)\s*\(')
PATTERN_VALIDATOR_CLASS = re.compile(r'Validator', re.IGNORECASE)
PATTERN_VALIDATE_FUNC = re.compile(r'validate', re.IGNORECASE)
PATTERN_SANITIZE_FUNC = re.compile(r'sanitize', re.IGNORECASE)
class SecurityScorer:
"""
Security dimension scoring engine.
This class evaluates Python scripts for security vulnerabilities and best practices
across four components:
1. Sensitive Data Exposure Prevention (25% of security score)
2. Safe File Operations (25% of security score)
3. Command Injection Prevention (25% of security score)
4. Input Validation Quality (25% of security score)
Attributes:
scripts: List of Python script paths to evaluate
verbose: Whether to output verbose logging
"""
def __init__(self, scripts: List[Path], verbose: bool = False):
"""
Initialize the SecurityScorer.
Args:
scripts: List of Path objects pointing to Python scripts
verbose: Enable verbose output for debugging
"""
self.scripts = scripts
self.verbose = verbose
self._findings: List[str] = []
def _log_verbose(self, message: str) -> None:
"""Log verbose message if verbose mode is enabled."""
if self.verbose:
print(f"[SECURITY] {message}")
def _get_script_content(self, script_path: Path) -> Optional[str]:
"""
Safely read script content.
Args:
script_path: Path to the Python script
Returns:
Script content as string, or None if read fails
"""
try:
return script_path.read_text(encoding='utf-8')
except Exception as e:
self._log_verbose(f"Failed to read {script_path}: {e}")
return None
def _clamp_score(self, score: int) -> int:
"""
Clamp score to valid range [MIN_SCORE, MAX_COMPONENT_SCORE].
Args:
score: Raw score value
Returns:
Score clamped to valid range
"""
return max(MIN_SCORE, min(score, MAX_COMPONENT_SCORE))
def _score_patterns(
self,
content: str,
script_name: str,
dangerous_patterns: List[Tuple[re.Pattern, str, int]],
safe_patterns: List[Tuple[re.Pattern, str, int]],
base_score: int
) -> Tuple[int, List[str]]:
"""
Generic pattern scoring method.
This method evaluates a script against lists of dangerous and safe patterns,
applying penalties for dangerous patterns found and bonuses for safe patterns.
Args:
content: Script content to analyze
script_name: Name of the script (for findings)
dangerous_patterns: List of (pattern, description, penalty) tuples
safe_patterns: List of (pattern, description, bonus) tuples
base_score: Starting score before adjustments
Returns:
Tuple of (final_score, findings_list)
"""
score = base_score
findings = []
# Check for dangerous patterns
for pattern, description, penalty in dangerous_patterns:
matches = pattern.findall(content)
if matches:
score += penalty # Penalty is negative
findings.append(f"{script_name}: {description} ({len(matches)} occurrence(s))")
# Check for safe patterns
for pattern, description, bonus in safe_patterns:
if pattern.search(content):
score += bonus
self._log_verbose(f"Safe pattern found in {script_name}: {description}")
return self._clamp_score(score), findings
def score_sensitive_data_exposure(self) -> Tuple[float, List[str]]:
"""
Score sensitive data exposure prevention.
Evaluates scripts for:
- Hardcoded passwords, API keys, secrets, tokens, private keys
- Multi-line string credentials
- F-string sensitive data
- Base64 encoded secrets
- JWT tokens
- Connection strings with credentials
Returns:
Tuple of (average_score, findings_list)
"""
if not self.scripts:
return float(MAX_COMPONENT_SCORE), []
scores = []
all_findings = []
# Define dangerous patterns with severity-based penalties
dangerous_patterns = [
(PATTERN_HARDCODED_PASSWORD, 'hardcoded password', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_API_KEY, 'hardcoded API key', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_SECRET, 'hardcoded secret', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_TOKEN, 'hardcoded token', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_PRIVATE_KEY, 'hardcoded private key', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_AWS_KEY, 'hardcoded AWS key', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_HARDCODED_AWS_SECRET, 'hardcoded AWS secret', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_MULTILINE_STRING, 'multi-line string credential', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_FSTRING_SENSITIVE, 'f-string sensitive data', HIGH_SEVERITY_PENALTY),
(PATTERN_BASE64_SECRET, 'base64 encoded secret', MEDIUM_SEVERITY_PENALTY),
(PATTERN_JWT_TOKEN, 'JWT token in code', HIGH_SEVERITY_PENALTY),
(PATTERN_CONNECTION_STRING, 'connection string with credentials', HIGH_SEVERITY_PENALTY),
]
# Safe patterns get bonus points
safe_patterns = [
(PATTERN_SAFE_ENV_VAR, 'safe environment variable usage', SAFE_PATTERN_BONUS),
]
for script_path in self.scripts:
content = self._get_script_content(script_path)
if content is None:
continue
score, findings = self._score_patterns(
content=content,
script_name=script_path.name,
dangerous_patterns=dangerous_patterns,
safe_patterns=safe_patterns,
base_score=BASE_SCORE_SENSITIVE_DATA
)
scores.append(score)
all_findings.extend(findings)
avg_score = sum(scores) / len(scores) if scores else 0.0
return avg_score, all_findings
def score_safe_file_operations(self) -> Tuple[float, List[str]]:
"""
Score safe file operations.
Evaluates scripts for:
- Path traversal vulnerabilities (basic, URL-encoded, Unicode, null bytes)
- Unsafe path construction
- Safe patterns (pathlib, basename, validation)
Returns:
Tuple of (average_score, findings_list)
"""
if not self.scripts:
return float(MAX_COMPONENT_SCORE), []
scores = []
all_findings = []
# Dangerous patterns with severity-based penalties
dangerous_patterns = [
(PATTERN_PATH_TRAVERSAL_BASIC, 'basic path traversal', HIGH_SEVERITY_PENALTY),
(PATTERN_PATH_TRAVERSAL_WINDOWS, 'Windows-style path traversal', HIGH_SEVERITY_PENALTY),
(PATTERN_PATH_TRAVERSAL_URL_ENCODED, 'URL-encoded path traversal', HIGH_SEVERITY_PENALTY),
(PATTERN_PATH_TRAVERSAL_UNICODE, 'Unicode-encoded path traversal', HIGH_SEVERITY_PENALTY),
(PATTERN_NULL_BYTE, 'null byte injection', HIGH_SEVERITY_PENALTY),
(PATTERN_PATH_CONCAT, 'potential path injection via concatenation', MEDIUM_SEVERITY_PENALTY),
(PATTERN_USER_INPUT_PATH, 'user input in path construction', MEDIUM_SEVERITY_PENALTY),
]
# Safe patterns get bonus points
safe_patterns = [
(PATTERN_SAFE_BASENAME, 'uses basename for safety', SAFE_PATTERN_BONUS),
(PATTERN_SAFE_PATHLIB, 'uses pathlib', SAFE_PATTERN_BONUS),
(PATTERN_PATH_VALIDATION, 'path validation', SAFE_PATTERN_BONUS),
(PATTERN_PATH_RESOLVE, 'path resolution', SAFE_PATTERN_BONUS),
]
for script_path in self.scripts:
content = self._get_script_content(script_path)
if content is None:
continue
score, findings = self._score_patterns(
content=content,
script_name=script_path.name,
dangerous_patterns=dangerous_patterns,
safe_patterns=safe_patterns,
base_score=BASE_SCORE_FILE_OPS
)
scores.append(score)
all_findings.extend(findings)
avg_score = sum(scores) / len(scores) if scores else 0.0
return avg_score, all_findings
def score_command_injection_prevention(self) -> Tuple[float, List[str]]:
"""
Score command injection prevention.
Evaluates scripts for:
- os.system(), os.popen() usage
- subprocess with shell=True
- eval(), exec() usage
- asyncio.create_subprocess_shell()
- pexpect.spawn()
- Safe patterns (shlex.quote, shell=False)
Returns:
Tuple of (average_score, findings_list)
"""
if not self.scripts:
return float(MAX_COMPONENT_SCORE), []
scores = []
all_findings = []
# Dangerous patterns with severity-based penalties
dangerous_patterns = [
(PATTERN_OS_SYSTEM, 'os.system usage - potential command injection', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_OS_POPEN, 'os.popen usage', HIGH_SEVERITY_PENALTY),
(PATTERN_EVAL, 'eval usage - code injection risk', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_EXEC, 'exec usage - code injection risk', CRITICAL_VULNERABILITY_PENALTY),
(PATTERN_SUBPROCESS_SHELL_TRUE, 'subprocess with shell=True', HIGH_SEVERITY_PENALTY),
(PATTERN_ASYNCIO_SHELL, 'asyncio.create_subprocess_shell()', HIGH_SEVERITY_PENALTY),
(PATTERN_PEXPECT_SPAWN, 'pexpect.spawn()', MEDIUM_SEVERITY_PENALTY),
]
# Safe patterns get bonus points
safe_patterns = [
(PATTERN_SAFE_SUBPROCESS, 'safe subprocess usage (shell=False)', GOOD_PRACTICE_BONUS),
(PATTERN_SHLEX_QUOTE, 'shell escaping with shlex.quote', GOOD_PRACTICE_BONUS),
(PATTERN_SHLEX_SPLIT, 'safe argument splitting with shlex.split', GOOD_PRACTICE_BONUS),
]
for script_path in self.scripts:
content = self._get_script_content(script_path)
if content is None:
continue
score, findings = self._score_patterns(
content=content,
script_name=script_path.name,
dangerous_patterns=dangerous_patterns,
safe_patterns=safe_patterns,
base_score=BASE_SCORE_COMMAND_INJECTION
)
scores.append(score)
all_findings.extend(findings)
avg_score = sum(scores) / len(scores) if scores else 0.0
return avg_score, all_findings
def score_input_validation(self) -> Tuple[float, List[str]]:
"""
Score input validation quality.
Evaluates scripts for:
- argparse usage for CLI validation
- Error handling patterns
- Type checking (isinstance)
- Regex validation
- Validation/sanitization functions
Returns:
Tuple of (average_score, suggestions_list)
"""
if not self.scripts:
return float(MAX_COMPONENT_SCORE), []
scores = []
suggestions = []
# Good validation patterns (each gives bonus points)
validation_patterns = [
(PATTERN_ARGPARSE, GOOD_PRACTICE_BONUS),
(PATTERN_TRY_EXCEPT, SAFE_PATTERN_BONUS),
(PATTERN_INPUT_CHECK, SAFE_PATTERN_BONUS),
(PATTERN_ISINSTANCE, SAFE_PATTERN_BONUS),
(PATTERN_ISDIGIT, SAFE_PATTERN_BONUS),
(PATTERN_REGEX_VALIDATION, SAFE_PATTERN_BONUS),
(PATTERN_VALIDATOR_CLASS, GOOD_PRACTICE_BONUS),
(PATTERN_VALIDATE_FUNC, SAFE_PATTERN_BONUS),
(PATTERN_SANITIZE_FUNC, SAFE_PATTERN_BONUS),
]
for script_path in self.scripts:
content = self._get_script_content(script_path)
if content is None:
continue
score = BASE_SCORE_INPUT_VALIDATION
# Check for validation patterns
for pattern, bonus in validation_patterns:
if pattern.search(content):
score += bonus
scores.append(self._clamp_score(score))
avg_score = sum(scores) / len(scores) if scores else 0.0
if avg_score < 15:
suggestions.append("Add input validation with argparse, type checking, and error handling")
return avg_score, suggestions
def get_overall_score(self) -> Dict[str, Any]:
"""
Calculate overall security score and return detailed results.
Returns:
Dictionary containing:
- overall_score: Weighted average of all components
- components: Individual component scores
- findings: List of security issues found
- suggestions: Improvement suggestions
"""
# Score each component
sensitive_score, sensitive_findings = self.score_sensitive_data_exposure()
file_ops_score, file_ops_findings = self.score_safe_file_operations()
command_injection_score, command_findings = self.score_command_injection_prevention()
input_validation_score, input_suggestions = self.score_input_validation()
# Calculate overall score (equal weight: 25% each)
overall_score = (
sensitive_score * 0.25 +
file_ops_score * 0.25 +
command_injection_score * 0.25 +
input_validation_score * 0.25
)
# Collect all findings
all_findings = sensitive_findings + file_ops_findings + command_findings
# Generate suggestions based on findings
suggestions = input_suggestions.copy()
if sensitive_findings:
suggestions.append("Remove hardcoded credentials and use environment variables or secure config")
if file_ops_findings:
suggestions.append("Validate and sanitize file paths, use pathlib for safe path handling")
if command_findings:
suggestions.append("Avoid shell=True in subprocess, use shlex.quote for shell arguments")
# Critical vulnerability check - if any critical issues, cap the score
critical_patterns = [
PATTERN_HARDCODED_PASSWORD, PATTERN_HARDCODED_API_KEY,
PATTERN_HARDCODED_PRIVATE_KEY, PATTERN_OS_SYSTEM,
PATTERN_EVAL, PATTERN_EXEC
]
has_critical = False
for script_path in self.scripts:
content = self._get_script_content(script_path)
if content is None:
continue
for pattern in critical_patterns:
if pattern.search(content):
has_critical = True
break
if has_critical:
break
if has_critical:
overall_score = min(overall_score, 30) # Cap at 30 if critical vulnerabilities exist
return {
'overall_score': round(overall_score, 1),
'components': {
'sensitive_data_exposure': round(sensitive_score, 1),
'safe_file_operations': round(file_ops_score, 1),
'command_injection_prevention': round(command_injection_score, 1),
'input_validation': round(input_validation_score, 1),
},
'findings': all_findings,
'suggestions': suggestions,
'has_critical_vulnerabilities': has_critical,
}