Infrastructure as Code Security

Comprehensive security scanning for Infrastructure as Code to catch misconfigurations before they become production vulnerabilities.

Core Principle: Security issues are cheaper to fix in code than in production.

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Quick Start

1. Identify IaC files (Terraform, K8s, CloudFormation, ARM)
2. Run snyk_iac_scan on the directory
3. Analyze misconfigurations by severity
4. Provide secure configuration alternatives

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Supported IaC Formats

Platform	File Types
Terraform	.tf, .tf.json, .tfvars
Terraform Plan	JSON plan output (terraform show -json)
Kubernetes	.yaml / .yml with apiVersion + kind
Helm	Chart templates (requires Chart.yaml)
AWS CloudFormation	.json / .yaml with AWSTemplateFormatVersion
Azure ARM	.json with $schema ARM URL
Serverless Framework	serverless.yml

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Phase 1: Discovery

Goal: Identify all IaC files that need scanning.

Check for these indicators to confirm IaC type:

• Terraform: .tf files, terraform.tfstate, provider blocks
• Kubernetes: YAML with apiVersion/kind, directories named k8s, manifests
• CloudFormation: AWSTemplateFormatVersion key, Resources section with AWS types
• Azure ARM: $schema containing deploymentTemplate

Then determine scan scope: single file, directory, or recursive.

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Phase 2: Execute Scan

Goal: Run appropriate IaC security scan.

Basic Scan

Run snyk_iac_scan with:
- path: <directory or file path>

Terraform with Variables

Run snyk_iac_scan with:
- path: <terraform directory>
- var_file: <path to .tfvars if using variables>

Terraform Plan (more accurate)

terraform plan -out=tfplan
terraform show -json tfplan > tfplan.json

Run snyk_iac_scan with:
- path: tfplan.json
- scan: "planned-values"  # or "resource-changes"

Custom Rules

Run snyk_iac_scan with:
- path: <directory>
- rules: <path to custom rules bundle>

---

Phase 3: Analyze Results

Goal: Understand and categorize misconfigurations.

Severity Assessment

Severity	Risk Level	Examples
Critical	Immediate risk	Public S3, open security groups
High	Significant risk	Missing encryption, excessive perms
Medium	Moderate risk	Missing logging, broad IAM
Low	Best practice	Missing tags, suboptimal config

Generate Summary

## IaC Security Scan Results

### Overview
| Severity | Count | Status |
|----------|-------|--------|
| Critical | X | 🔴 Block |
| High | Y | 🟠 Fix Required |
| Medium | Z | 🟡 Recommended |
| Low | W | 🔵 Optional |

### Critical Issues
| Resource | Issue | Location |
|----------|-------|----------|
| aws_s3_bucket.data | Public access enabled | main.tf:45 |
| aws_security_group.web | Open to 0.0.0.0/0 on port 22 | network.tf:23 |

### High Issues
| Resource | Issue | Location |
|----------|-------|----------|
| aws_rds_instance.db | Encryption not enabled | database.tf:12 |

Categorize by Domain

Group issues for easier remediation:

• Network Security: Security groups, Network ACLs, Load balancer config, VPC settings
• Data Protection: Encryption at rest/in transit, Backup configuration, Key management
• Access Control: IAM policies, Service accounts, RBAC settings, API permissions
• Logging & Monitoring: CloudTrail/audit logs, Access logging, Alerting config

---

Phase 4: Remediation

Goal: Provide secure configuration fixes. Apply the pattern below to each finding; representative examples follow.

Terraform Fixes

S3 Bucket — Block Public Access

# Insecure
resource "aws_s3_bucket" "data" {
  bucket = "my-bucket"
}

# Secure
resource "aws_s3_bucket" "data" {
  bucket = "my-bucket"
}

resource "aws_s3_bucket_public_access_block" "data" {
  bucket = aws_s3_bucket.data.id

  block_public_acls       = true
  block_public_policy     = true
  ignore_public_acls      = true
  restrict_public_buckets = true
}

Security Group — Restrict Access

# Insecure - open to world
resource "aws_security_group" "web" {
  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]  # BAD
  }
}

# Secure - restricted to VPN/internal range
resource "aws_security_group" "web" {
  ingress {
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["10.0.0.0/8"]
  }
}

RDS — Enable Encryption

# Secure
resource "aws_db_instance" "main" {
  engine              = "postgres"
  instance_class      = "db.t3.micro"
  storage_encrypted   = true
  kms_key_id          = aws_kms_key.rds.arn
  deletion_protection = true
}

Kubernetes Fixes

Pod Security — Non-Root User & Resource Limits

apiVersion: v1
kind: Pod
spec:
  securityContext:
    runAsNonRoot: true
    runAsUser: 1000
  containers:
  - name: app
    image: myapp
    securityContext:
      allowPrivilegeEscalation: false
      readOnlyRootFilesystem: true
      capabilities:
        drop:
          - ALL
    resources:
      limits:
        cpu: "500m"
        memory: "512Mi"
      requests:
        cpu: "200m"
        memory: "256Mi"

Network Policy — Restrict Traffic

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: app-network-policy
spec:
  podSelector:
    matchLabels:
      app: myapp
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          name: allowed-namespace

CloudFormation Fixes

S3 Bucket — Encryption & Public Access Block

Resources:
  DataBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: aws:kms
              KMSMasterKeyID: !Ref DataBucketKey
      PublicAccessBlockConfiguration:
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true

---

Phase 5: Verification

Goal: Confirm fixes are effective.

Re-scan After Changes

Run snyk_iac_scan with:
- path: <same directory>

For Terraform, regenerate and scan the plan:

terraform plan -out=tfplan.new
terraform show -json tfplan.new > tfplan.new.json

Report Improvements

## Fix Verification

| Severity | Before | After | Change |
|----------|--------|-------|--------|
| Critical | 2 | 0 | -2 ✅ |
| High | 5 | 1 | -4 ✅ |
| Medium | 8 | 6 | -2 ✅ |

### Remaining Issues
- 1 High: Third-party module - opened issue
- 6 Medium: Accepted risk (documented)

---

Best Practices

Prevention

1. Scan in CI/CD: Fail builds with critical issues
2. Pre-commit hooks: Catch issues before commit
3. Module security: Scan reusable modules
4. Policy as code: Define custom rules for org standards

Policy File Usage

Create .snyk to manage exceptions:

ignore:
  SNYK-CC-TF-123:
    - '*':
        reason: 'Accepted risk - internal development environment'
        expires: 2025-06-01
        created: 2024-01-15

Custom Rules

For organization-specific requirements:

1. Write rules in Rego (OPA) format
2. Bundle as .tar.gz
3. Pass to scan with --rules option

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Error Handling

Error	Solutions
Could not read Terraform state	Run terraform init; check state backend; scan .tf files directly
Invalid HCL syntax	Run terraform validate; check syntax; ensure all variables are defined
Could not parse plan file	Regenerate with terraform show -json; check Terraform version compatibility; verify JSON validity

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Constraints

1. Scan before apply: Never apply unscanned IaC
2. Block on critical: Critical issues must be fixed
3. Document exceptions: Use .snyk policy for accepted risks
4. Validate plans: Prefer plan scanning over file scanning for Terraform
5. Continuous monitoring: Re-scan when dependencies update