snyk-security

name	snyk-security
description	Runs Snyk CLI security scans and fixes the vulnerabilities found. Covers four domains: source code (SAST via snyk code test), open-source dependencies (SCA via snyk test), container images (snyk container test), and infrastructure-as-code files such as Terraform, Kubernetes YAML, and CloudFormation (snyk iac test). Use this skill whenever the user wants to scan for vulnerabilities, audit dependencies, secure a Dockerfile or container image, check IaC for misconfigurations, or asks "is my code/app/image/infra secure?". Also trigger for requests like "fix security issues", "run a security scan", "check for CVEs", "find hardcoded secrets", or "review my Terraform for security problems" even if Snyk is not mentioned by name.
license	MIT
compatibility	Requires the Snyk CLI to be installed and authenticated (snyk auth or SNYK_TOKEN env var). Compatible with Claude Code on macOS, Linux, and Windows. Requires internet access for Snyk vulnerability database lookups. Supported languages and ecosystems vary by scan type; see reference files for per-domain details.
metadata	{"author":"lirantal","version":"1.0.0"}

Snyk Security Scanning

Instructions

The goal is never just to run a scan — it's to leave the project with its security issues actually resolved. Each use case below follows the same core loop: scan → analyze → fix → verify → repeat until clean.

Before starting any scan, verify Snyk is ready:

snyk --version   # confirms CLI is installed
snyk auth        # opens browser to authenticate (one-time setup)

If Snyk is not installed, help the user install it first:

• npm: npm install -g snyk
• Homebrew: brew tap snyk/tap && brew install snyk

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Step 1: Identify the scan scope

Determine which domains apply to this project. When the user's request is specific ("scan my Dockerfile"), go directly to that use case. When it's ambiguous ("make my project secure"), run all applicable scans.

What to scan	Use case	CLI command
Source code (JS, Python, Java, Go, etc.)	Use Case A	snyk code test
npm, pip, Maven, Go modules, etc.	Use Case B	snyk test
Docker images	Use Case C	snyk container test
Terraform, Kubernetes YAML, CloudFormation	Use Case D	snyk iac test

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Step 2: Run the scan (choose the use case)

Use Case A — Secure Project Source Code (SAST)

Finds vulnerabilities in code the developer wrote: SQL injection, XSS, hardcoded secrets, insecure crypto, path traversal, etc.

Reference: references/code-security.md — command flags, fix patterns, and secure coding rules to apply during remediation.

snyk code test

Expected output: a list of findings grouped by severity, each with file path, line number, vulnerability type, and data flow showing how untrusted input reaches the sink.

For each finding, prioritize Critical and High first. Read the data flow to understand the attack vector, then fix the root cause in the source code. Re-run to confirm the finding is gone before moving to the next one.

Done when: snyk code test returns no Critical or High findings.

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Use Case B — Secure Project Dependencies (SCA)

Finds known CVEs in open-source libraries — both direct and transitive dependencies.

Reference: references/dependency-security.md — package manager specifics, upgrade paths, ignore workflow, and CI integration patterns.

# Install dependencies first so Snyk can read the full tree
npm install   # or: pip install -r requirements.txt, mvn install, go mod download, etc.

snyk test
# Monorepos or multiple manifests:
snyk test --all-projects

Expected output: vulnerabilities grouped by package, each with CVE ID, severity, affected version range, and fix path (upgrade / patch / no fix available).

For each finding: upgrade direct dependencies to the fixed version, run snyk fix for auto-applicable patches, or document an ignore with justification and expiry as a last resort. Re-run after each fix to confirm and check for newly exposed issues.

Done when: snyk test returns no Critical or High findings.

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Use Case C — Secure Container Images

Finds OS package CVEs, application dependency CVEs, and Dockerfile misconfigurations in Docker images.

Reference: references/container-security.md — base image selection, Dockerfile best practices, multi-stage builds, rebuild/re-scan workflow.

snyk container test IMAGE:TAG
# With Dockerfile for enhanced misconfiguration analysis:
snyk container test IMAGE:TAG --file=Dockerfile

Expected output: OS vulnerabilities grouped by base image layer, application dependency vulnerabilities, and Dockerfile issues (running as root, missing USER, secrets in ENV, etc.). Snyk also suggests specific base image upgrades that would reduce the total vulnerability count.

Fix by upgrading the base image (FROM line) to the version Snyk recommends, fixing any app dependency CVEs in the source manifest, and correcting Dockerfile issues. Rebuild and re-scan to verify.

docker build -t IMAGE:NEW-TAG .
snyk container test IMAGE:NEW-TAG --file=Dockerfile

Done when: The rebuilt image passes snyk container test with no Critical or High severity findings.

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Use Case D — Secure Infrastructure-as-Code

Finds misconfigurations in Terraform, Kubernetes, CloudFormation, ARM templates, Helm charts, and Serverless files before they reach production.

Reference: references/iac-security.md — fix patterns with before/after examples for AWS, GCP, Azure, and Kubernetes.

snyk iac test ./infrastructure/
# Or target specific files:
snyk iac test main.tf
snyk iac test k8s/deployment.yaml

Expected output: findings grouped by severity, each with the affected resource name, the exact misconfigured attribute path (e.g., aws_s3_bucket.data > acl), the security risk it creates, and remediation guidance.

Fix by modifying the IaC file to correct the misconfiguration — apply least privilege, enable encryption, restrict public access. Re-run to verify. The principle across all IaC fixes is: default to deny, encrypt at rest and in transit, minimize blast radius.

Done when: snyk iac test returns no Critical or High findings.

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Step 3: Monitor ongoing security

After resolving all findings, register the project for continuous monitoring:

snyk monitor

Snyk will alert when new vulnerabilities are published that affect the project, so issues are caught before they become incidents.

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Examples

Example 1: Full project security audit

User says: "Can you do a full security scan of this project?"

Actions:

1. Check Snyk is installed and authenticated
2. Run snyk code test — review and fix any High/Critical source code findings
3. Run npm install then snyk test — upgrade vulnerable dependencies
4. If a Dockerfile exists, run snyk container test IMAGE:TAG --file=Dockerfile
5. If IaC files exist, run snyk iac test ./infra
6. Run snyk monitor to register for ongoing alerts

Result: All Critical and High findings resolved across all applicable domains. Project is registered for continuous monitoring.

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Example 2: Fix a specific CVE in a dependency

User says: "Snyk says lodash 4.17.15 has a prototype pollution vulnerability, can you fix it?"

Actions:

1. Run snyk test to confirm the finding and see the upgrade path
2. Check if a direct upgrade resolves it: npm install lodash@latest
3. Re-run snyk test to confirm the vulnerability is gone
4. If lodash is a transitive dep, identify which direct dependency pulls it in and upgrade that, or use an overrides entry in package.json

Result: snyk test no longer reports the prototype pollution CVE. package.json and package-lock.json are updated with the safe version.

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Example 3: Secure a Dockerfile before deployment

User says: "We're about to push a new container to production, scan it first"

Actions:

1. Run snyk container test myapp:latest --file=Dockerfile
2. Review OS vulnerabilities — check if Snyk suggests a base image upgrade
3. Review Dockerfile issues — look for missing USER directive, secrets in ENV, etc.
4. Update the FROM line to the recommended base image version
5. Fix any Dockerfile misconfigurations (add USER, move secrets to runtime env)
6. Run docker build -t myapp:latest-secure . and re-scan to verify

Result: Container image rebuilt with updated base image and secure Dockerfile. snyk container test passes with no Critical or High findings.

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Example 4: Review Terraform for security issues

User says: "Review my Terraform files for any security problems before we apply"

Actions:

1. Run snyk iac test ./terraform/
2. Identify Critical/High findings — commonly: public S3 buckets, missing encryption, over-permissive security groups, no CloudTrail logging
3. Fix each misconfiguration using patterns from references/iac-security.md
4. Re-run snyk iac test to confirm all issues are resolved
5. Confirm the Terraform plan looks correct after changes

Result: Terraform files updated with security fixes. snyk iac test returns no Critical or High findings. Safe to apply.

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Troubleshooting

Error: snyk: command not found Cause: Snyk CLI is not installed. Solution: npm install -g snyk or brew tap snyk/tap && brew install snyk

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Error: Authentication failed. Please run snyk auth. Cause: Not authenticated with Snyk. Solution: Run snyk auth (opens a browser to log in) or set the SNYK_TOKEN environment variable with a token from https://app.snyk.io/account.

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Error: Could not detect supported target files in [path] Cause: Snyk couldn't find a package manifest, or dependencies haven't been installed. Solution: Run the appropriate install command first (npm install, pip install -r requirements.txt, etc.), then re-run. Use --file=<manifest> to point Snyk at a specific file.

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Error: snyk code test exits with no output or "SAST is not enabled" Cause: Snyk Code (SAST) may not be enabled for the organization. Solution: Log into https://app.snyk.io, go to Settings, and enable Snyk Code. If using a free account, confirm Snyk Code is included in the plan.

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Exit code 1 vs exit code 2

• Exit code 1 means vulnerabilities were found — this is expected and working correctly.
• Exit code 2 means an error occurred (bad auth, missing files, network issue). Only exit code 2 indicates something is wrong with the scan itself.