578 lines
18 KiB
Python
578 lines
18 KiB
Python
#!/usr/bin/env python3
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"""
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terraform-patterns: Terraform Security Scanner
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Scan .tf files for common security issues including hardcoded secrets,
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overly permissive IAM policies, open security groups, missing encryption,
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and sensitive variable misuse.
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Usage:
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python scripts/tf_security_scanner.py ./terraform
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python scripts/tf_security_scanner.py ./terraform --output json
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python scripts/tf_security_scanner.py ./terraform --strict
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"""
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import argparse
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import json
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import os
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import re
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import sys
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from pathlib import Path
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# --- Demo Terraform File ---
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DEMO_TF = """
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provider "aws" {
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region = "us-east-1"
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access_key = "AKIAIOSFODNN7EXAMPLE"
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secret_key = "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY"
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}
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variable "db_password" {
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type = string
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default = "supersecret123"
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}
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resource "aws_instance" "web" {
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ami = "ami-12345678"
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instance_type = "t3.micro"
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tags = {
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Name = "web-server"
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}
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}
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resource "aws_security_group" "web" {
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name = "web-sg"
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ingress {
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from_port = 22
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to_port = 22
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protocol = "tcp"
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cidr_blocks = ["0.0.0.0/0"]
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}
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ingress {
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from_port = 0
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to_port = 65535
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protocol = "tcp"
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cidr_blocks = ["0.0.0.0/0"]
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}
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egress {
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from_port = 0
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to_port = 0
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protocol = "-1"
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cidr_blocks = ["0.0.0.0/0"]
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}
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}
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resource "aws_iam_policy" "admin" {
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name = "admin-policy"
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policy = jsonencode({
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Version = "2012-10-17"
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Statement = [
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{
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Effect = "Allow"
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Action = "*"
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Resource = "*"
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}
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]
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})
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}
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resource "aws_s3_bucket" "data" {
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bucket = "my-data-bucket"
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}
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resource "aws_db_instance" "main" {
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engine = "mysql"
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instance_class = "db.t3.micro"
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password = "hardcoded-password"
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publicly_accessible = true
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skip_final_snapshot = true
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}
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"""
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# --- Security Rules ---
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SECRET_PATTERNS = [
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{
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"id": "SEC001",
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"name": "aws_access_key",
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"severity": "critical",
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"pattern": r'(?:access_key|aws_access_key_id)\s*=\s*"(AKIA[A-Z0-9]{16})"',
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"message": "AWS access key hardcoded in configuration",
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"fix": "Use environment variables, AWS profiles, or IAM roles instead",
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},
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{
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"id": "SEC002",
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"name": "aws_secret_key",
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"severity": "critical",
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"pattern": r'(?:secret_key|aws_secret_access_key)\s*=\s*"[A-Za-z0-9/+=]{40}"',
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"message": "AWS secret key hardcoded in configuration",
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"fix": "Use environment variables, AWS profiles, or IAM roles instead",
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},
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{
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"id": "SEC003",
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"name": "generic_password",
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"severity": "critical",
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"pattern": r'(?:password|passwd)\s*=\s*"[^"]{4,}"',
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"message": "Password hardcoded in resource or provider configuration",
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"fix": "Use a variable with sensitive = true, or fetch from Vault/SSM/Secrets Manager",
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},
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{
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"id": "SEC004",
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"name": "generic_secret",
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"severity": "critical",
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"pattern": r'(?:secret|token|api_key)\s*=\s*"[^"]{8,}"',
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"message": "Secret or token hardcoded in configuration",
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"fix": "Use a sensitive variable or secrets manager",
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},
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{
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"id": "SEC005",
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"name": "private_key",
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"severity": "critical",
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"pattern": r'-----BEGIN (?:RSA |EC |DSA )?PRIVATE KEY-----',
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"message": "Private key embedded in Terraform configuration",
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"fix": "Reference key file with file() function or use secrets manager",
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},
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]
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IAM_PATTERNS = [
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{
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"id": "SEC010",
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"name": "iam_wildcard_action",
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"severity": "critical",
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"pattern": r'Action\s*=\s*"\*"',
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"message": "IAM policy with wildcard Action = \"*\" — grants all permissions",
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"fix": "Scope Action to specific services and operations",
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},
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{
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"id": "SEC011",
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"name": "iam_wildcard_resource",
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"severity": "high",
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"pattern": r'Resource\s*=\s*"\*"',
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"message": "IAM policy with wildcard Resource = \"*\" — applies to all resources",
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"fix": "Scope Resource to specific ARN patterns",
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},
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{
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"id": "SEC012",
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"name": "iam_star_star",
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"severity": "critical",
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"pattern": r'Action\s*=\s*"\*"[^}]*Resource\s*=\s*"\*"',
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"message": "IAM policy with Action=* AND Resource=* — effectively admin access",
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"fix": "Follow least-privilege: grant only the specific actions and resources needed",
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},
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]
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NETWORK_PATTERNS = [
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{
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"id": "SEC020",
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"name": "sg_ssh_open",
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"severity": "critical",
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"pattern": None, # Custom check
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"message": "Security group allows SSH (port 22) from 0.0.0.0/0",
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"fix": "Restrict to known CIDR blocks, or use SSM Session Manager instead",
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},
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{
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"id": "SEC021",
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"name": "sg_rdp_open",
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"severity": "critical",
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"pattern": None, # Custom check
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"message": "Security group allows RDP (port 3389) from 0.0.0.0/0",
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"fix": "Restrict to known CIDR blocks, or use a bastion host",
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},
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{
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"id": "SEC022",
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"name": "sg_all_ports",
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"severity": "critical",
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"pattern": None, # Custom check
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"message": "Security group allows all ports (0-65535) from 0.0.0.0/0",
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"fix": "Open only the specific ports your application needs",
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},
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]
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ENCRYPTION_PATTERNS = [
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{
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"id": "SEC030",
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"name": "s3_no_encryption",
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"severity": "high",
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"pattern": None, # Custom check
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"message": "S3 bucket without server-side encryption configuration",
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"fix": "Add aws_s3_bucket_server_side_encryption_configuration resource",
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},
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{
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"id": "SEC031",
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"name": "rds_no_encryption",
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"severity": "high",
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"pattern": None, # Custom check
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"message": "RDS instance without storage encryption",
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"fix": "Set storage_encrypted = true on aws_db_instance",
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},
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{
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"id": "SEC032",
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"name": "ebs_no_encryption",
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"severity": "medium",
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"pattern": None, # Custom check
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"message": "EBS volume without encryption",
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"fix": "Set encrypted = true on aws_ebs_volume or enable account-level default encryption",
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},
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]
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ACCESS_PATTERNS = [
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{
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"id": "SEC040",
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"name": "rds_public",
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"severity": "high",
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"pattern": r'publicly_accessible\s*=\s*true',
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"message": "RDS instance is publicly accessible",
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"fix": "Set publicly_accessible = false and access via VPC/bastion",
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},
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{
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"id": "SEC041",
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"name": "s3_public_acl",
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"severity": "high",
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"pattern": r'acl\s*=\s*"public-read(?:-write)?"',
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"message": "S3 bucket with public ACL",
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"fix": "Remove public ACL and add aws_s3_bucket_public_access_block",
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},
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]
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def find_tf_files(directory):
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"""Find all .tf files in a directory (non-recursive)."""
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tf_files = {}
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for entry in sorted(os.listdir(directory)):
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if entry.endswith(".tf"):
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filepath = os.path.join(directory, entry)
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with open(filepath, encoding="utf-8") as f:
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tf_files[entry] = f.read()
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return tf_files
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def check_regex_rules(content, rules):
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"""Run regex-based security rules against content."""
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findings = []
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for rule in rules:
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if rule["pattern"] is None:
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continue
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for match in re.finditer(rule["pattern"], content, re.MULTILINE | re.IGNORECASE):
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": rule["message"],
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"fix": rule["fix"],
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"line": match.group(0).strip()[:80],
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})
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return findings
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def check_security_groups(content):
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"""Custom check for open security groups."""
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findings = []
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# Parse ingress blocks within security group resources
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sg_blocks = re.finditer(
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r'resource\s+"aws_security_group"[^{]*\{(.*?)\n\}',
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content,
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re.DOTALL,
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)
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for sg_match in sg_blocks:
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sg_body = sg_match.group(1)
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ingress_blocks = re.finditer(
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r'ingress\s*\{(.*?)\}', sg_body, re.DOTALL
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)
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for ingress in ingress_blocks:
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block = ingress.group(1)
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has_open_cidr = '0.0.0.0/0' in block or '::/0' in block
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if not has_open_cidr:
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continue
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from_port_match = re.search(r'from_port\s*=\s*(\d+)', block)
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to_port_match = re.search(r'to_port\s*=\s*(\d+)', block)
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if from_port_match and to_port_match:
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from_port = int(from_port_match.group(1))
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to_port = int(to_port_match.group(1))
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# SSH open
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if from_port <= 22 <= to_port:
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rule = next(r for r in NETWORK_PATTERNS if r["id"] == "SEC020")
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": rule["message"],
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"fix": rule["fix"],
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"line": f"ingress port 22, cidr 0.0.0.0/0",
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})
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# RDP open
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if from_port <= 3389 <= to_port:
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rule = next(r for r in NETWORK_PATTERNS if r["id"] == "SEC021")
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": rule["message"],
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"fix": rule["fix"],
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"line": f"ingress port 3389, cidr 0.0.0.0/0",
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})
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# All ports open
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if from_port == 0 and to_port >= 65535:
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rule = next(r for r in NETWORK_PATTERNS if r["id"] == "SEC022")
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": rule["message"],
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"fix": rule["fix"],
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"line": f"ingress ports 0-65535, cidr 0.0.0.0/0",
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})
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return findings
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def check_encryption(content):
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"""Custom check for missing encryption on storage resources."""
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findings = []
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# S3 buckets without encryption
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s3_buckets = re.findall(
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r'resource\s+"aws_s3_bucket"\s+"([^"]+)"', content
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)
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s3_encryption = re.findall(
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r'resource\s+"aws_s3_bucket_server_side_encryption_configuration"', content
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)
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# Also check inline encryption (older format)
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inline_encryption = re.findall(
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r'server_side_encryption_configuration', content
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)
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if s3_buckets and not s3_encryption and not inline_encryption:
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rule = next(r for r in ENCRYPTION_PATTERNS if r["id"] == "SEC030")
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for bucket in s3_buckets:
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": f"{rule['message']} (bucket: {bucket})",
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"fix": rule["fix"],
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"line": f'aws_s3_bucket.{bucket}',
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})
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# RDS without encryption
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rds_blocks = re.finditer(
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r'resource\s+"aws_db_instance"\s+"([^"]+)"\s*\{(.*?)\n\}',
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content,
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re.DOTALL,
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)
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for rds_match in rds_blocks:
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name = rds_match.group(1)
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body = rds_match.group(2)
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if 'storage_encrypted' not in body or re.search(
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r'storage_encrypted\s*=\s*false', body
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):
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rule = next(r for r in ENCRYPTION_PATTERNS if r["id"] == "SEC031")
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": f"{rule['message']} (instance: {name})",
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"fix": rule["fix"],
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"line": f'aws_db_instance.{name}',
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})
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# EBS volumes without encryption
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ebs_blocks = re.finditer(
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r'resource\s+"aws_ebs_volume"\s+"([^"]+)"\s*\{(.*?)\n\}',
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content,
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re.DOTALL,
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)
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for ebs_match in ebs_blocks:
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name = ebs_match.group(1)
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body = ebs_match.group(2)
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if 'encrypted' not in body or re.search(
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r'encrypted\s*=\s*false', body
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):
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rule = next(r for r in ENCRYPTION_PATTERNS if r["id"] == "SEC032")
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findings.append({
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"id": rule["id"],
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"severity": rule["severity"],
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"message": f"{rule['message']} (volume: {name})",
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"fix": rule["fix"],
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"line": f'aws_ebs_volume.{name}',
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})
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return findings
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def check_sensitive_variables(content):
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"""Check if variables that look like secrets are marked sensitive."""
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findings = []
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var_blocks = re.finditer(
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r'variable\s+"([^"]+)"\s*\{(.*?)\n\}',
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content,
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re.DOTALL,
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)
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secret_names = ["password", "secret", "token", "api_key", "private_key", "credentials"]
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for var_match in var_blocks:
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name = var_match.group(1)
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body = var_match.group(2)
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name_lower = name.lower()
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if any(s in name_lower for s in secret_names):
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if not re.search(r'sensitive\s*=\s*true', body):
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findings.append({
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"id": "SEC050",
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"severity": "medium",
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"message": f"Variable '{name}' appears to be a secret but is not marked sensitive = true",
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"fix": "Add sensitive = true to prevent the value from appearing in logs and plan output",
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"line": f'variable "{name}"',
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})
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# Check for hardcoded default
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default_match = re.search(r'default\s*=\s*"([^"]+)"', body)
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if default_match and len(default_match.group(1)) > 0:
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findings.append({
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"id": "SEC051",
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"severity": "critical",
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"message": f"Variable '{name}' has a hardcoded default value for a secret",
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"fix": "Remove the default value — require it to be passed at runtime via tfvars or env",
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"line": f'variable "{name}" default = "{default_match.group(1)[:20]}..."',
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})
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return findings
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def scan_content(content, strict=False):
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"""Run all security checks on content."""
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findings = []
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findings.extend(check_regex_rules(content, SECRET_PATTERNS))
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findings.extend(check_regex_rules(content, IAM_PATTERNS))
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findings.extend(check_regex_rules(content, ACCESS_PATTERNS))
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findings.extend(check_security_groups(content))
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findings.extend(check_encryption(content))
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findings.extend(check_sensitive_variables(content))
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if strict:
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for f in findings:
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if f["severity"] == "medium":
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f["severity"] = "high"
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elif f["severity"] == "low":
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f["severity"] = "medium"
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# Deduplicate by (id, line)
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seen = set()
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unique = []
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for f in findings:
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key = (f["id"], f.get("line", ""))
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if key not in seen:
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seen.add(key)
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unique.append(f)
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findings = unique
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# Sort by severity
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severity_order = {"critical": 0, "high": 1, "medium": 2, "low": 3}
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findings.sort(key=lambda f: severity_order.get(f["severity"], 4))
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return findings
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def generate_report(content, output_format="text", strict=False):
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"""Generate security scan report."""
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findings = scan_content(content, strict)
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# Score
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deductions = {"critical": 25, "high": 15, "medium": 5, "low": 2}
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score = max(0, 100 - sum(deductions.get(f["severity"], 0) for f in findings))
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counts = {
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"critical": sum(1 for f in findings if f["severity"] == "critical"),
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"high": sum(1 for f in findings if f["severity"] == "high"),
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"medium": sum(1 for f in findings if f["severity"] == "medium"),
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"low": sum(1 for f in findings if f["severity"] == "low"),
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}
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result = {
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"score": score,
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"findings": findings,
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"finding_counts": counts,
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"total_findings": len(findings),
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}
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if output_format == "json":
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print(json.dumps(result, indent=2))
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return result
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# Text output
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print(f"\n{'=' * 60}")
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print(f" Terraform Security Scan Report")
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print(f"{'=' * 60}")
|
|
print(f" Score: {score}/100")
|
|
print()
|
|
print(f" Findings: {counts['critical']} critical | {counts['high']} high | {counts['medium']} medium | {counts['low']} low")
|
|
print(f"{'─' * 60}")
|
|
|
|
for f in findings:
|
|
icon = {"critical": "!!!", "high": "!!", "medium": "!", "low": "~"}.get(f["severity"], "?")
|
|
print(f"\n [{f['id']}] {icon} {f['severity'].upper()}")
|
|
print(f" {f['message']}")
|
|
if f.get("line"):
|
|
print(f" Match: {f['line']}")
|
|
print(f" Fix: {f['fix']}")
|
|
|
|
if not findings:
|
|
print("\n No security issues found. Configuration looks clean.")
|
|
|
|
print(f"\n{'=' * 60}\n")
|
|
return result
|
|
|
|
|
|
def main():
|
|
parser = argparse.ArgumentParser(
|
|
description="terraform-patterns: Terraform security scanner"
|
|
)
|
|
parser.add_argument(
|
|
"target", nargs="?",
|
|
help="Path to Terraform directory or .tf file (omit for demo)",
|
|
)
|
|
parser.add_argument(
|
|
"--output", "-o",
|
|
choices=["text", "json"],
|
|
default="text",
|
|
help="Output format (default: text)",
|
|
)
|
|
parser.add_argument(
|
|
"--strict",
|
|
action="store_true",
|
|
help="Strict mode — elevate warnings to higher severity",
|
|
)
|
|
args = parser.parse_args()
|
|
|
|
if args.target:
|
|
target = Path(args.target)
|
|
if target.is_dir():
|
|
tf_files = find_tf_files(str(target))
|
|
if not tf_files:
|
|
print(f"Error: No .tf files found in {args.target}", file=sys.stderr)
|
|
sys.exit(1)
|
|
content = "\n".join(tf_files.values())
|
|
elif target.is_file() and target.suffix == ".tf":
|
|
content = target.read_text(encoding="utf-8")
|
|
else:
|
|
print(f"Error: {args.target} is not a directory or .tf file", file=sys.stderr)
|
|
sys.exit(1)
|
|
else:
|
|
print("No target provided. Running demo scan...\n")
|
|
content = DEMO_TF
|
|
|
|
generate_report(content, args.output, args.strict)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|