Serverless Runtime Security: Protecting the Invisible Infrastructure
setec@astronomy:~/blog$ cat serverless-runtime-security:-protecting-the-invisible-infrastructure.md
Serverless Runtime Security: Protecting the Invisible Infrastructure
Comprehensive guide to serverless runtime security, from container hardening to runtime threat detection and incident response in AWS Lambda environments.
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Serverless Runtime Security: Protecting the Invisible Infrastructure
In serverless computing, the runtime is your last line of defense. While AWS manages the underlying infrastructure, the responsibility for runtime security falls squarely on your shoulders. This invisible layer—where your code executes, where secrets are processed, and where data flows—represents one of the most critical and often overlooked attack surfaces in modern cloud applications.
This comprehensive guide explores advanced serverless runtime security techniques, from hardening execution environments to detecting sophisticated attacks in real-time.
The Serverless Runtime Threat Model
Understanding the unique attack vectors targeting serverless runtimes is crucial for effective defense:
Lambda Runtime Architecture Vulnerabilities
# runtime_threat_analysis.py - Analyze runtime-specific threats
import os
import sys
import inspect
import subprocess
import json
import time
from typing import Dict, Any, List
import logging
import hashlib
logger = logging.getLogger()
class RuntimeThreatAnalyzer:
"""Analyze and detect runtime-specific security threats"""
def __init__(self):
# Initialize threat detection signatures
self.threat_signatures = {
'code_injection': [
r'eval\s*\(',
r'exec\s*\(',
r'compile\s*\(',
r'__import__\s*\(',
r'getattr\s*\(',
r'setattr\s*\(',
],
'command_injection': [
r'subprocess\.',
r'os\.system',
r'os\.popen',
r'commands\.',
r'shell=True'
],
'path_traversal': [
r'\.\./',
r'\.\.\\',
r'/etc/passwd',
r'/proc/',
r'~/'
],
'environment_manipulation': [
r'os\.environ',
r'sys\.path',
r'sys\.modules',
r'globals\s*\(',
r'locals\s*\('
]
}
# Runtime monitoring state
self.runtime_state = {
'start_time': time.time(),
'function_calls': [],
'file_access_attempts': [],
'network_connections': [],
'environment_changes': []
}
def analyze_runtime_environment(self, context) -> Dict[str, Any]:
"""Comprehensive runtime environment analysis"""
environment_analysis = {
'timestamp': time.time(),
'function_name': getattr(context, 'function_name', 'unknown'),
'function_version': getattr(context, 'function_version', 'unknown'),
'remaining_time': getattr(context, 'get_remaining_time_in_millis', lambda: 0)(),
'memory_limit': getattr(context, 'memory_limit_in_mb', 'unknown'),
'request_id': getattr(context, 'aws_request_id', 'unknown')
}
# Analyze environment variables for sensitive data exposure
environment_analysis['env_analysis'] = self.analyze_environment_variables()
# Check for suspicious modules loaded
environment_analysis['module_analysis'] = self.analyze_loaded_modules()
# Analyze file system permissions
environment_analysis['filesystem_analysis'] = self.analyze_filesystem_permissions()
# Check for runtime modifications
environment_analysis['runtime_modifications'] = self.detect_runtime_modifications()
return environment_analysis
def analyze_environment_variables(self) -> Dict[str, Any]:
"""Analyze environment variables for security issues"""
env_analysis = {
'total_vars': len(os.environ),
'suspicious_vars': [],
'exposed_secrets': [],
'aws_vars': {}
}
# Patterns that might indicate secrets
secret_patterns = [
r'password', r'passwd', r'pwd',
r'secret', r'key', r'token',
r'api[_-]?key', r'access[_-]?key',
r'private[_-]?key', r'auth'
]
for var_name, var_value in os.environ.items():
var_lower = var_name.lower()
# Check for AWS-specific variables
if var_name.startswith(('AWS_', 'LAMBDA_')):
env_analysis['aws_vars'][var_name] = len(var_value)
# Check for potential secrets
for pattern in secret_patterns:
if re.search(pattern, var_lower):
env_analysis['suspicious_vars'].append({
'name': var_name,
'pattern': pattern,
'value_length': len(var_value),
'starts_with': var_value[:10] if var_value else '',
'risk_level': 'high' if len(var_value) > 20 else 'medium'
})
# Check for exposed secrets (actual secret values)
if self.is_potential_secret(var_value):
env_analysis['exposed_secrets'].append({
'name': var_name,
'type': self.classify_secret_type(var_value),
'value_hash': hashlib.sha256(var_value.encode()).hexdigest()[:16]
})
return env_analysis
def analyze_loaded_modules(self) -> Dict[str, Any]:
"""Analyze loaded Python modules for suspicious activity"""
module_analysis = {
'total_modules': len(sys.modules),
'suspicious_modules': [],
'dangerous_modules': [],
'recently_loaded': []
}
# Known dangerous modules (for code execution)
dangerous_modules = [
'subprocess', 'os', 'sys', 'eval', 'exec',
'compile', 'importlib', 'runpy', 'code'
]
# Suspicious modules (often used in attacks)
suspicious_modules = [
'pickle', 'marshal', 'types', 'ctypes',
'gc', 'inspect', 'ast', 'dis'
]
for module_name, module_obj in sys.modules.items():
if module_name in dangerous_modules:
module_analysis['dangerous_modules'].append({
'name': module_name,
'file': getattr(module_obj, '__file__', 'built-in'),
'version': getattr(module_obj, '__version__', 'unknown')
})
if module_name in suspicious_modules:
module_analysis['suspicious_modules'].append({
'name': module_name,
'file': getattr(module_obj, '__file__', 'built-in')
})
# Check for recently loaded modules (potential dynamic loading)
if hasattr(module_obj, '__file__') and module_obj.__file__:
try:
stat = os.stat(module_obj.__file__)
load_time = stat.st_mtime
# If loaded in the last 60 seconds
if time.time() - load_time < 60:
module_analysis['recently_loaded'].append({
'name': module_name,
'file': module_obj.__file__,
'load_time': load_time
})
except:
pass
return module_analysis
def analyze_filesystem_permissions(self) -> Dict[str, Any]:
"""Analyze filesystem access patterns and permissions"""
filesystem_analysis = {
'writable_paths': [],
'sensitive_files': [],
'temp_directory_usage': {},
'unusual_access_patterns': []
}
# Check common writable locations
writable_locations = ['/tmp', '/dev/shm', '/var/tmp']
for location in writable_locations:
if os.path.exists(location) and os.access(location, os.W_OK):
try:
files = os.listdir(location)
filesystem_analysis['writable_paths'].append({
'path': location,
'writable': True,
'file_count': len(files),
'files': files[:10] # First 10 files
})
except PermissionError:
filesystem_analysis['writable_paths'].append({
'path': location,
'writable': True,
'accessible': False
})
# Check for sensitive file access
sensitive_files = [
'/etc/passwd', '/etc/shadow', '/etc/hosts',
'/proc/version', '/proc/cpuinfo', '/proc/meminfo'
]
for file_path in sensitive_files:
if os.path.exists(file_path):
try:
with open(file_path, 'r') as f:
content = f.read(100) # First 100 chars
filesystem_analysis['sensitive_files'].append({
'path': file_path,
'accessible': True,
'content_preview': content
})
except PermissionError:
filesystem_analysis['sensitive_files'].append({
'path': file_path,
'accessible': False
})
return filesystem_analysis
def detect_runtime_modifications(self) -> Dict[str, Any]:
"""Detect modifications to the runtime environment"""
modifications = {
'sys_path_changes': [],
'module_patches': [],
'builtin_modifications': [],
'global_namespace_pollution': []
}
# Check sys.path modifications
original_sys_path = [
'/var/runtime',
'/opt/python',
'/var/task',
'/opt/python/lib/python3.9/site-packages'
]
current_paths = sys.path
for path in current_paths:
if path not in original_sys_path and path:
modifications['sys_path_changes'].append(path)
# Check for monkey patching of built-in functions
dangerous_builtins = ['eval', 'exec', 'compile', '__import__']
for builtin_name in dangerous_builtins:
if hasattr(__builtins__, builtin_name):
builtin_func = getattr(__builtins__, builtin_name)
if hasattr(builtin_func, '__wrapped__'): # Likely wrapped/patched
modifications['builtin_modifications'].append({
'name': builtin_name,
'wrapped': True,
'wrapper': str(builtin_func)
})
return modifications
def is_potential_secret(self, value: str) -> bool:
"""Determine if a value looks like a secret"""
if not isinstance(value, str) or len(value) < 10:
return False
# Check for common secret patterns
secret_indicators = [
len(value) > 20, # Long values
any(c.isupper() and c.islower() for c in value), # Mixed case
any(c.isdigit() for c in value), # Contains numbers
any(c in '!@#$%^&*()_+-=' for c in value), # Special characters
]
return sum(secret_indicators) >= 2
def classify_secret_type(self, value: str) -> str:
"""Classify the type of secret"""
if value.startswith('sk-'):
return 'openai_api_key'
elif value.startswith('xoxb-'):
return 'slack_bot_token'
elif value.startswith('ghp_'):
return 'github_personal_token'
elif len(value) == 32 and all(c in '0123456789abcdef' for c in value):
return 'md5_hash'
elif len(value) == 64 and all(c in '0123456789abcdef' for c in value):
return 'sha256_hash'
elif 'AKIA' in value:
return 'aws_access_key'
else:
return 'unknown'
class RuntimeSecurityMonitor:
"""Real-time runtime security monitoring"""
def __init__(self):
self.threat_analyzer = RuntimeThreatAnalyzer()
self.security_events = []
self.monitoring_enabled = True
# Hook into critical functions
self.setup_security_hooks()
def setup_security_hooks(self):
"""Set up hooks for monitoring critical operations"""
# Wrap dangerous functions
self.original_eval = __builtins__.get('eval', eval)
self.original_exec = __builtins__.get('exec', exec)
# Replace with monitored versions
__builtins__['eval'] = self.monitored_eval
__builtins__['exec'] = self.monitored_exec
# Hook file operations
self.original_open = open
def monitored_eval(self, expression, globals=None, locals=None):
"""Monitored version of eval function"""
self.log_security_event(
'DANGEROUS_FUNCTION_CALL',
{
'function': 'eval',
'expression': str(expression)[:100],
'caller': self.get_caller_info()
},
'HIGH'
)
# Allow evaluation but log it
return self.original_eval(expression, globals, locals)
def monitored_exec(self, object, globals=None, locals=None):
"""Monitored version of exec function"""
self.log_security_event(
'DANGEROUS_FUNCTION_CALL',
{
'function': 'exec',
'object': str(object)[:100],
'caller': self.get_caller_info()
},
'HIGH'
)
# Allow execution but log it
return self.original_exec(object, globals, locals)
def get_caller_info(self) -> Dict[str, Any]:
"""Get information about the calling function"""
frame = inspect.currentframe()
try:
# Go up the stack to find the actual caller
caller_frame = frame.f_back.f_back
return {
'filename': caller_frame.f_code.co_filename,
'function_name': caller_frame.f_code.co_name,
'line_number': caller_frame.f_lineno,
'locals_count': len(caller_frame.f_locals)
}
except:
return {'error': 'Could not determine caller'}
finally:
del frame
def log_security_event(self, event_type: str, details: Dict[str, Any], severity: str):
"""Log security events for analysis"""
security_event = {
'timestamp': time.time(),
'event_type': event_type,
'details': details,
'severity': severity,
'runtime_context': {
'memory_usage': self.get_memory_usage(),
'execution_time': time.time() - self.threat_analyzer.runtime_state['start_time']
}
}
self.security_events.append(security_event)
# Send to CloudWatch for real-time alerting
self.send_security_alert(security_event)
def get_memory_usage(self) -> Dict[str, Any]:
"""Get current memory usage statistics"""
try:
import psutil
process = psutil.Process()
memory_info = process.memory_info()
return {
'rss': memory_info.rss,
'vms': memory_info.vms,
'percent': process.memory_percent()
}
except ImportError:
# psutil not available, use basic metrics
import resource
usage = resource.getrusage(resource.RUSAGE_SELF)
return {
'max_rss': usage.ru_maxrss,
'shared_memory': usage.ru_ixrss,
'data_memory': usage.ru_idrss
}
def send_security_alert(self, security_event: Dict[str, Any]):
"""Send security alerts to monitoring systems"""
if security_event['severity'] in ['HIGH', 'CRITICAL']:
try:
# Send to CloudWatch
import boto3
cloudwatch = boto3.client('cloudwatch')
cloudwatch.put_metric_data(
Namespace='Lambda/Security',
MetricData=[
{
'MetricName': 'SecurityEvents',
'Dimensions': [
{
'Name': 'EventType',
'Value': security_event['event_type']
},
{
'Name': 'Severity',
'Value': security_event['severity']
}
],
'Value': 1,
'Unit': 'Count'
}
]
)
# Send to SQS for immediate processing
if security_event['severity'] == 'CRITICAL':
sqs = boto3.client('sqs')
queue_url = os.environ.get('SECURITY_ALERTS_QUEUE')
if queue_url:
sqs.send_message(
QueueUrl=queue_url,
MessageBody=json.dumps(security_event),
MessageAttributes={
'Severity': {
'StringValue': security_event['severity'],
'DataType': 'String'
}
}
)
except Exception as e:
logger.error(f"Failed to send security alert: {e}")
def get_security_report(self) -> Dict[str, Any]:
"""Generate comprehensive security report"""
report = {
'monitoring_duration': time.time() - self.threat_analyzer.runtime_state['start_time'],
'total_events': len(self.security_events),
'events_by_severity': {},
'events_by_type': {},
'recent_events': self.security_events[-10:], # Last 10 events
'recommendations': []
}
# Group events by severity
for event in self.security_events:
severity = event['severity']
report['events_by_severity'][severity] = report['events_by_severity'].get(severity, 0) + 1
event_type = event['event_type']
report['events_by_type'][event_type] = report['events_by_type'].get(event_type, 0) + 1
# Generate recommendations
if report['events_by_severity'].get('HIGH', 0) > 0:
report['recommendations'].append('Review high-severity security events immediately')
if report['events_by_type'].get('DANGEROUS_FUNCTION_CALL', 0) > 3:
report['recommendations'].append('Consider code review for excessive use of dangerous functions')
return report
# Global security monitor instance
security_monitor = RuntimeSecurityMonitor()
def secure_lambda_handler(event, context):
"""Lambda handler with comprehensive runtime security monitoring"""
try:
# Initialize runtime analysis
runtime_analysis = security_monitor.threat_analyzer.analyze_runtime_environment(context)
# Log runtime initialization
security_monitor.log_security_event(
'RUNTIME_INITIALIZED',
runtime_analysis,
'INFO'
)
# Process the actual request
request_type = event.get('type', 'unknown')
if request_type == 'security_analysis':
# Return security analysis
return {
'statusCode': 200,
'body': json.dumps({
'runtime_analysis': runtime_analysis,
'security_report': security_monitor.get_security_report()
})
}
# Example of dangerous operation that would be detected
elif request_type == 'dangerous_operation':
# This would trigger security monitoring
user_input = event.get('code', 'print("Hello World")')
# DANGEROUS: This would be logged and monitored
exec(user_input)
return {
'statusCode': 200,
'body': json.dumps({
'message': 'Dangerous operation completed',
'security_events': len(security_monitor.security_events)
})
}
# Normal operation
else:
return {
'statusCode': 200,
'body': json.dumps({
'message': 'Request processed safely',
'runtime_analysis': runtime_analysis
})
}
except Exception as e:
# Log security exception
security_monitor.log_security_event(
'RUNTIME_EXCEPTION',
{
'error': str(e),
'error_type': type(e).__name__,
'caller': security_monitor.get_caller_info()
},
'HIGH'
)
logger.error(f"Runtime security error: {e}")
return {
'statusCode': 500,
'body': json.dumps({
'error': 'Internal server error',
'security_events': len(security_monitor.security_events)
})
}Advanced Runtime Hardening Techniques
Container Security and Sandboxing
# runtime_hardening.py - Advanced runtime hardening
import os
import sys
import resource
import signal
import tempfile
import subprocess
from typing import Dict, Any, Optional
import logging
logger = logging.getLogger()
class RuntimeHardeningManager:
"""Implement runtime hardening techniques for Lambda functions"""
def __init__(self):
self.security_limits = {
'max_memory': 256 * 1024 * 1024, # 256MB
'max_cpu_time': 30, # 30 seconds
'max_open_files': 100,
'max_processes': 10,
'max_file_size': 10 * 1024 * 1024 # 10MB
}
self.restricted_modules = [
'ctypes', 'subprocess', 'multiprocessing',
'threading', 'socket', 'urllib', 'http'
]
# Apply hardening on initialization
self.apply_resource_limits()
self.setup_signal_handlers()
self.restrict_module_imports()
def apply_resource_limits(self):
"""Apply resource limits to the runtime environment"""
try:
# Memory limit
resource.setrlimit(
resource.RLIMIT_AS,
(self.security_limits['max_memory'], self.security_limits['max_memory'])
)
# CPU time limit
resource.setrlimit(
resource.RLIMIT_CPU,
(self.security_limits['max_cpu_time'], self.security_limits['max_cpu_time'])
)
# File descriptor limit
resource.setrlimit(
resource.RLIMIT_NOFILE,
(self.security_limits['max_open_files'], self.security_limits['max_open_files'])
)
# Process limit
resource.setrlimit(
resource.RLIMIT_NPROC,
(self.security_limits['max_processes'], self.security_limits['max_processes'])
)
# File size limit
resource.setrlimit(
resource.RLIMIT_FSIZE,
(self.security_limits['max_file_size'], self.security_limits['max_file_size'])
)
logger.info("Runtime resource limits applied successfully")
except Exception as e:
logger.error(f"Failed to apply resource limits: {e}")
def setup_signal_handlers(self):
"""Set up signal handlers for security monitoring"""
def security_signal_handler(signum, frame):
"""Handle security-related signals"""
signal_names = {
signal.SIGALRM: 'ALARM',
signal.SIGXCPU: 'CPU_LIMIT_EXCEEDED',
signal.SIGXFSZ: 'FILE_SIZE_LIMIT_EXCEEDED'
}
signal_name = signal_names.get(signum, f'SIGNAL_{signum}')
logger.critical(f"Security signal received: {signal_name}")
# Log security incident
security_monitor.log_security_event(
'RESOURCE_LIMIT_EXCEEDED',
{
'signal': signal_name,
'frame_info': {
'filename': frame.f_code.co_filename,
'function': frame.f_code.co_name,
'line': frame.f_lineno
}
},
'CRITICAL'
)
# Terminate execution
sys.exit(1)
# Register signal handlers
signal.signal(signal.SIGALRM, security_signal_handler) # Alarm
signal.signal(signal.SIGXCPU, security_signal_handler) # CPU limit
signal.signal(signal.SIGXFSZ, security_signal_handler) # File size limit
def restrict_module_imports(self):
"""Restrict imports of dangerous modules"""
original_import = __builtins__['__import__']
def restricted_import(name, globals=None, locals=None, fromlist=(), level=0):
"""Restricted import function"""
# Check if module is restricted
if name in self.restricted_modules:
# Log the attempt
security_monitor.log_security_event(
'RESTRICTED_MODULE_IMPORT',
{
'module': name,
'caller': security_monitor.get_caller_info()
},
'HIGH'
)
# Allow import but with warning
logger.warning(f"Restricted module imported: {name}")
return original_import(name, globals, locals, fromlist, level)
# Replace the import function
__builtins__['__import__'] = restricted_import
def create_secure_temp_directory(self) -> str:
"""Create a secure temporary directory with restricted permissions"""
try:
# Create temporary directory
temp_dir = tempfile.mkdtemp(prefix='lambda_secure_')
# Set restrictive permissions (owner only)
os.chmod(temp_dir, 0o700)
logger.info(f"Secure temp directory created: {temp_dir}")
return temp_dir
except Exception as e:
logger.error(f"Failed to create secure temp directory: {e}")
raise
def validate_file_access(self, file_path: str, operation: str) -> bool:
"""Validate file access requests"""
# Normalize path
normalized_path = os.path.normpath(file_path)
# Restricted paths
restricted_paths = [
'/etc/', '/bin/', '/sbin/', '/usr/bin/',
'/usr/sbin/', '/boot/', '/dev/', '/sys/'
]
# Check for path traversal
if '..' in normalized_path:
security_monitor.log_security_event(
'PATH_TRAVERSAL_ATTEMPT',
{
'file_path': file_path,
'normalized_path': normalized_path,
'operation': operation
},
'HIGH'
)
return False
# Check restricted paths
for restricted in restricted_paths:
if normalized_path.startswith(restricted):
security_monitor.log_security_event(
'RESTRICTED_PATH_ACCESS',
{
'file_path': file_path,
'restricted_path': restricted,
'operation': operation
},
'HIGH'
)
return False
return True
def secure_file_open(self, file_path: str, mode: str = 'r', **kwargs):
"""Secure wrapper for file opening"""
# Validate file access
if not self.validate_file_access(file_path, f'open_{mode}'):
raise PermissionError(f"Access denied to {file_path}")
# Log file access
security_monitor.log_security_event(
'FILE_ACCESS',
{
'file_path': file_path,
'mode': mode,
'caller': security_monitor.get_caller_info()
},
'INFO'
)
# Use original open function
return security_monitor.original_open(file_path, mode, **kwargs)
class RuntimeIntegrityChecker:
"""Check runtime integrity and detect tampering"""
def __init__(self):
# Store initial state checksums
self.initial_checksums = self.calculate_runtime_checksums()
def calculate_runtime_checksums(self) -> Dict[str, str]:
"""Calculate checksums of critical runtime components"""
checksums = {}
try:
# Python executable checksum
python_path = sys.executable
if os.path.exists(python_path):
with open(python_path, 'rb') as f:
content = f.read()
checksums['python_executable'] = hashlib.sha256(content).hexdigest()
# Critical module checksums
critical_modules = ['os', 'sys', 'subprocess', 'importlib']
for module_name in critical_modules:
if module_name in sys.modules:
module = sys.modules[module_name]
if hasattr(module, '__file__') and module.__file__:
try:
with open(module.__file__, 'rb') as f:
content = f.read()
checksums[f'module_{module_name}'] = hashlib.sha256(content).hexdigest()
except:
pass
except Exception as e:
logger.error(f"Failed to calculate runtime checksums: {e}")
return checksums
def verify_runtime_integrity(self) -> Dict[str, Any]:
"""Verify runtime integrity against initial state"""
current_checksums = self.calculate_runtime_checksums()
integrity_report = {
'timestamp': time.time(),
'integrity_violations': [],
'new_components': [],
'missing_components': [],
'overall_status': 'CLEAN'
}
# Check for modifications
for component, initial_checksum in self.initial_checksums.items():
if component not in current_checksums:
integrity_report['missing_components'].append(component)
integrity_report['overall_status'] = 'COMPROMISED'
elif current_checksums[component] != initial_checksum:
integrity_report['integrity_violations'].append({
'component': component,
'initial_checksum': initial_checksum,
'current_checksum': current_checksums[component]
})
integrity_report['overall_status'] = 'COMPROMISED'
# Check for new components
for component in current_checksums:
if component not in self.initial_checksums:
integrity_report['new_components'].append(component)
integrity_report['overall_status'] = 'MODIFIED'
# Log integrity violations
if integrity_report['overall_status'] != 'CLEAN':
security_monitor.log_security_event(
'RUNTIME_INTEGRITY_VIOLATION',
integrity_report,
'CRITICAL'
)
return integrity_report
# Global hardening manager
hardening_manager = RuntimeHardeningManager()
integrity_checker = RuntimeIntegrityChecker()
# Replace built-in open with secure version
__builtins__['open'] = hardening_manager.secure_file_openRuntime Incident Response System
# runtime_incident_response.py - Automated incident response for runtime threats
import json
import boto3
import time
from datetime import datetime, timedelta
from typing import Dict, Any, List
from dataclasses import dataclass
from enum import Enum
import logging
logger = logging.getLogger()
class ThreatLevel(Enum):
LOW = "low"
MEDIUM = "medium"
HIGH = "high"
CRITICAL = "critical"
class ResponseAction(Enum):
MONITOR = "monitor"
ALERT = "alert"
QUARANTINE = "quarantine"
TERMINATE = "terminate"
@dataclass
class SecurityIncident:
id: str
timestamp: float
threat_level: ThreatLevel
event_type: str
details: Dict[str, Any]
affected_resources: List[str]
response_actions: List[ResponseAction]
class RuntimeIncidentResponse:
"""Automated incident response system for runtime security threats"""
def __init__(self):
self.incident_store = boto3.resource('dynamodb').Table(
os.environ.get('INCIDENT_TABLE', 'runtime-incidents')
)
self.sns_client = boto3.client('sns')
self.lambda_client = boto3.client('lambda')
# Response playbooks
self.response_playbooks = {
'CODE_INJECTION': {
ThreatLevel.HIGH: [ResponseAction.QUARANTINE, ResponseAction.ALERT],
ThreatLevel.CRITICAL: [ResponseAction.TERMINATE, ResponseAction.ALERT]
},
'COMMAND_INJECTION': {
ThreatLevel.HIGH: [ResponseAction.QUARANTINE, ResponseAction.ALERT],
ThreatLevel.CRITICAL: [ResponseAction.TERMINATE, ResponseAction.ALERT]
},
'PATH_TRAVERSAL_ATTEMPT': {
ThreatLevel.MEDIUM: [ResponseAction.MONITOR, ResponseAction.ALERT],
ThreatLevel.HIGH: [ResponseAction.QUARANTINE, ResponseAction.ALERT]
},
'RUNTIME_INTEGRITY_VIOLATION': {
ThreatLevel.CRITICAL: [ResponseAction.TERMINATE, ResponseAction.ALERT]
},
'RESOURCE_LIMIT_EXCEEDED': {
ThreatLevel.HIGH: [ResponseAction.QUARANTINE, ResponseAction.ALERT]
}
}
# Incident correlation rules
self.correlation_rules = [
{
'name': 'Multiple injection attempts',
'conditions': {
'event_types': ['CODE_INJECTION', 'COMMAND_INJECTION'],
'count': 3,
'time_window': 300 # 5 minutes
},
'escalation': ThreatLevel.CRITICAL
},
{
'name': 'Rapid security events',
'conditions': {
'any_security_event': True,
'count': 10,
'time_window': 60 # 1 minute
},
'escalation': ThreatLevel.HIGH
}
]
def process_security_event(self, event_type: str, details: Dict[str, Any],
severity: str, context: Dict[str, Any]) -> SecurityIncident:
"""Process security event and trigger incident response"""
# Map severity to threat level
threat_level_mapping = {
'LOW': ThreatLevel.LOW,
'MEDIUM': ThreatLevel.MEDIUM,
'HIGH': ThreatLevel.HIGH,
'CRITICAL': ThreatLevel.CRITICAL
}
threat_level = threat_level_mapping.get(severity, ThreatLevel.LOW)
# Create incident
incident = SecurityIncident(
id=self.generate_incident_id(event_type, context),
timestamp=time.time(),
threat_level=threat_level,
event_type=event_type,
details=details,
affected_resources=[
context.get('function_name', 'unknown'),
context.get('aws_request_id', 'unknown')
],
response_actions=[]
)
# Apply correlation rules
incident = self.apply_correlation_rules(incident)
# Determine response actions
incident.response_actions = self.determine_response_actions(
incident.event_type,
incident.threat_level
)
# Execute response actions
self.execute_response_actions(incident)
# Store incident
self.store_incident(incident)
return incident
def apply_correlation_rules(self, incident: SecurityIncident) -> SecurityIncident:
"""Apply correlation rules to detect attack patterns"""
current_time = time.time()
for rule in self.correlation_rules:
conditions = rule['conditions']
time_window = conditions.get('time_window', 300)
required_count = conditions.get('count', 1)
# Query recent incidents
recent_incidents = self.get_recent_incidents(
time_window,
conditions.get('event_types', [incident.event_type])
)
if len(recent_incidents) >= required_count:
# Escalate threat level
escalation_level = rule['escalation']
if escalation_level.value > incident.threat_level.value:
logger.warning(f"Escalating incident due to rule: {rule['name']}")
incident.threat_level = escalation_level
incident.details['escalation_rule'] = rule['name']
incident.details['correlated_incidents'] = [
i['id'] for i in recent_incidents
]
return incident
def determine_response_actions(self, event_type: str, threat_level: ThreatLevel) -> List[ResponseAction]:
"""Determine appropriate response actions based on threat"""
playbook = self.response_playbooks.get(event_type, {})
actions = playbook.get(threat_level, [ResponseAction.MONITOR])
return actions
def execute_response_actions(self, incident: SecurityIncident):
"""Execute response actions for the incident"""
for action in incident.response_actions:
try:
if action == ResponseAction.MONITOR:
self.action_monitor(incident)
elif action == ResponseAction.ALERT:
self.action_alert(incident)
elif action == ResponseAction.QUARANTINE:
self.action_quarantine(incident)
elif action == ResponseAction.TERMINATE:
self.action_terminate(incident)
logger.info(f"Executed response action: {action.value} for incident {incident.id}")
except Exception as e:
logger.error(f"Failed to execute action {action.value}: {e}")
def action_monitor(self, incident: SecurityIncident):
"""Enhanced monitoring action"""
# Increase logging verbosity
logger.setLevel(logging.DEBUG)
# Send monitoring alert
self.send_notification(
f"Security incident monitoring activated: {incident.id}",
incident.details,
'info'
)
def action_alert(self, incident: SecurityIncident):
"""Send security alerts"""
alert_message = {
'incident_id': incident.id,
'threat_level': incident.threat_level.value,
'event_type': incident.event_type,
'timestamp': incident.timestamp,
'affected_resources': incident.affected_resources,
'details': incident.details
}
# Send to SNS topic
topic_arn = os.environ.get('SECURITY_ALERTS_TOPIC')
if topic_arn:
self.sns_client.publish(
TopicArn=topic_arn,
Subject=f'Runtime Security Alert: {incident.event_type}',
Message=json.dumps(alert_message, indent=2)
)
# Send to Slack/Teams webhook if configured
webhook_url = os.environ.get('SECURITY_WEBHOOK_URL')
if webhook_url:
self.send_webhook_alert(webhook_url, alert_message)
def action_quarantine(self, incident: SecurityIncident):
"""Quarantine affected Lambda function"""
function_name = incident.affected_resources[0]
try:
# Update function configuration to disable it temporarily
self.lambda_client.update_function_configuration(
FunctionName=function_name,
Environment={
'Variables': {
'QUARANTINE_MODE': 'true',
'QUARANTINE_REASON': incident.event_type,
'QUARANTINE_TIMESTAMP': str(incident.timestamp)
}
}
)
logger.warning(f"Function {function_name} has been quarantined")
except Exception as e:
logger.error(f"Failed to quarantine function {function_name}: {e}")
def action_terminate(self, incident: SecurityIncident):
"""Terminate current execution and prevent further invocations"""
function_name = incident.affected_resources[0]
try:
# Set reserved concurrency to 0 to prevent new invocations
self.lambda_client.put_reserved_concurrency(
FunctionName=function_name,
ReservedConcurrencyLimit=0
)
logger.critical(f"Function {function_name} has been terminated")
# Terminate current execution
os._exit(1)
except Exception as e:
logger.error(f"Failed to terminate function {function_name}: {e}")
def get_recent_incidents(self, time_window: int, event_types: List[str]) -> List[Dict]:
"""Get recent incidents for correlation analysis"""
cutoff_time = time.time() - time_window
try:
response = self.incident_store.scan(
FilterExpression=boto3.dynamodb.conditions.Attr('timestamp').gt(cutoff_time),
ProjectionExpression='id, event_type, timestamp, threat_level'
)
incidents = []
for item in response.get('Items', []):
if item['event_type'] in event_types:
incidents.append(item)
return incidents
except Exception as e:
logger.error(f"Failed to query recent incidents: {e}")
return []
def store_incident(self, incident: SecurityIncident):
"""Store incident in DynamoDB for analysis"""
try:
item = {
'id': incident.id,
'timestamp': incident.timestamp,
'threat_level': incident.threat_level.value,
'event_type': incident.event_type,
'details': incident.details,
'affected_resources': incident.affected_resources,
'response_actions': [action.value for action in incident.response_actions],
'ttl': int(time.time() + (90 * 24 * 3600)) # 90 days retention
}
self.incident_store.put_item(Item=item)
except Exception as e:
logger.error(f"Failed to store incident: {e}")
def generate_incident_id(self, event_type: str, context: Dict[str, Any]) -> str:
"""Generate unique incident ID"""
timestamp = int(time.time() * 1000)
function_name = context.get('function_name', 'unknown')
request_id = context.get('aws_request_id', 'unknown')[:8]
return f"{event_type}_{function_name}_{request_id}_{timestamp}"
def send_webhook_alert(self, webhook_url: str, alert_data: Dict[str, Any]):
"""Send alert via webhook"""
try:
import requests
payload = {
"text": f"🚨 Runtime Security Alert: {alert_data['event_type']}",
"attachments": [{
"color": "danger" if alert_data['threat_level'] in ['high', 'critical'] else "warning",
"fields": [
{
"title": "Incident ID",
"value": alert_data['incident_id'],
"short": True
},
{
"title": "Threat Level",
"value": alert_data['threat_level'].upper(),
"short": True
},
{
"title": "Affected Resources",
"value": ", ".join(alert_data['affected_resources']),
"short": False
}
]
}]
}
requests.post(webhook_url, json=payload, timeout=5)
except Exception as e:
logger.error(f"Failed to send webhook alert: {e}")
# Global incident response system
incident_response = RuntimeIncidentResponse()
# Integration with security monitor
def enhanced_security_event_handler(event_type: str, details: Dict[str, Any],
severity: str, context: Dict[str, Any]):
"""Enhanced security event handler with incident response"""
# Process through incident response system
incident = incident_response.process_security_event(
event_type, details, severity, context
)
logger.info(f"Security incident created: {incident.id} ({incident.threat_level.value})")
return incident
def hardened_lambda_handler(event, context):
"""Production-ready Lambda handler with comprehensive runtime security"""
# Check if function is quarantined
if os.environ.get('QUARANTINE_MODE') == 'true':
return {
'statusCode': 503,
'body': json.dumps({
'error': 'Function quarantined due to security incident',
'quarantine_reason': os.environ.get('QUARANTINE_REASON', 'unknown'),
'quarantine_timestamp': os.environ.get('QUARANTINE_TIMESTAMP', 'unknown')
})
}
# Verify runtime integrity
integrity_report = integrity_checker.verify_runtime_integrity()
if integrity_report['overall_status'] == 'COMPROMISED':
enhanced_security_event_handler(
'RUNTIME_INTEGRITY_VIOLATION',
integrity_report,
'CRITICAL',
{'function_name': context.function_name, 'aws_request_id': context.aws_request_id}
)
try:
# Process request with full security monitoring
return secure_lambda_handler(event, context)
except Exception as e:
# Handle security exceptions
enhanced_security_event_handler(
'RUNTIME_EXCEPTION',
{
'error': str(e),
'error_type': type(e).__name__
},
'HIGH',
{'function_name': context.function_name, 'aws_request_id': context.aws_request_id}
)
raiseConclusion: Securing the Serverless Runtime
Runtime security in serverless environments requires a fundamentally different approach than traditional infrastructure security. The ephemeral nature of serverless execution environments, combined with the shared responsibility model, creates unique challenges that demand innovative solutions.
Key Principles for Serverless Runtime Security:
- Defense in Depth: Layer multiple security controls throughout the runtime environment
- Real-time Monitoring: Implement continuous monitoring for anomalous behavior and threats
- Automated Response: Build automated incident response capabilities that can react faster than human operators
- Integrity Verification: Continuously verify the integrity of the runtime environment and code
- Least Privilege Execution: Apply strict resource limits and access controls at the runtime level
Critical Implementation Areas:
- Runtime Hardening: Implement resource limits, module restrictions, and access controls
- Threat Detection: Deploy real-time monitoring for injection attacks, privilege escalation, and anomalous behavior
- Incident Response: Build automated response capabilities that can quarantine or terminate compromised functions
- Integrity Monitoring: Continuously verify runtime integrity and detect tampering attempts
- Security Logging: Implement comprehensive logging and alerting for all security-relevant events
The future of serverless security lies in building intelligent, self-defending runtime environments that can detect, respond to, and recover from sophisticated attacks without human intervention. As serverless computing continues to evolve, so too must our approach to securing these invisible, ephemeral execution environments.
Remember: in serverless computing, the runtime is your last line of defense. Make it count.