Agent skill
sast-analysis
Perform codebase analysis and architecture mapping as the first phase of a security assessment. Explores the tech stack, frameworks, entry points, data flows, and trust boundaries. Outputs sast/architecture.md. Run this before any vulnerability detection skill. Use when asked to analyze a codebase for security or when sast/architecture.md does not yet exist.
Install this agent skill to your Project
npx add-skill https://github.com/utkusen/sast-skills/tree/main/sast-files/.agents/skills/sast-analysis
SKILL.md
Codebase Analysis
You are performing the first phase of a security assessment. Your goal is to deeply understand the codebase. You are NOT looking for specific vulnerabilities yet. This is pure reconnaissance.
Create a sast/ folder in the project root (if it doesn't already exist). This phase produces one output file inside it:
sast/architecture.md — technology stack, architecture, entry points, data flows
Phase 1: Technology Reconnaissance
Explore the codebase and identify:
- Languages: All programming languages used and their versions if specified
- Frameworks: Web frameworks, ORM layers, template engines, task queues
- Package managers & dependencies: Lock files, dependency manifests (package.json, requirements.txt, go.mod, Gemfile, pom.xml, etc.)
- Infrastructure hints: Dockerfiles, docker-compose, Kubernetes manifests, Terraform, CI/CD configs
- Databases: SQL, NoSQL, cache layers, message brokers — look at connection strings, ORM models, migration files
- Authentication & authorization: Auth libraries, middleware, session configs, OAuth/OIDC providers, JWT usage, API key patterns
- External integrations: Third-party APIs, payment processors, email services, cloud SDKs, webhook handlers
- Entry points: HTTP routes, GraphQL schemas, gRPC service definitions, CLI commands, WebSocket handlers, scheduled jobs, message consumers
Start by reading dependency manifests, project configs, and directory structure. Then drill into source code to confirm findings.
Phase 2: Architecture Mapping
Based on Phase 1, build a mental model of:
- Service boundaries: Is this a monolith or microservices? What talks to what?
- Data flow: How does user input enter the system, get processed, get stored, and get returned?
- Trust boundaries: Where does the system transition between trusted and untrusted contexts? (e.g., user input -> backend, backend -> database, service -> service, server -> client)
- Privilege levels: What roles/permissions exist? How are they enforced? Is there an admin panel?
- Sensitive data inventory: PII, credentials, tokens, financial data, health records — where is each stored and how does it move?
Write the results of Phase 1 and Phase 2 to sast/architecture.md. Use this format:
# Architecture: [Project Name]
## Technology Stack
| Category | Details |
|---|---|
| Languages | ... |
| Frameworks | ... |
| Databases | ... |
| Auth mechanism | ... |
| Infrastructure | ... |
| External services | ... |
## Architecture Overview
[Describe the architecture: monolith vs microservices, how components interact,
main modules and their responsibilities]
## Data Flow
[Trace how user input enters the system, gets processed, stored, and returned.
Cover the primary flows (e.g., registration, login, core business actions).]
## Entry Points
| Entry Point | Type | Auth Required | Description |
|---|---|---|---|
| ... | HTTP/GraphQL/WS/etc. | Yes/No | ... |
## Trust Boundaries
[List each trust boundary and what crosses it]
## Sensitive Data Inventory
| Data Type | Where Stored | How Accessed | Protection |
|---|---|---|---|
| ... | ... | ... | ... |
Important Reminders
- Do NOT report specific vulnerabilities (like "line 42 has SQL injection"). That comes in later phases.
- Be thorough in exploration. Read actual source code, not just config files. Look at how auth middleware is applied, how queries are built, how file uploads are handled.
- If the codebase is large, prioritize security-sensitive areas: auth, payment, data access, file handling, admin functionality.
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
sast-sqli
Detect SQL injection vulnerabilities in a codebase using a three-phase approach: recon (find unsafe SQL construction sites), batched verify (trace user input to those sites in parallel subagents, 3 sites each), and merge (consolidate batch results). Covers string concat, f-strings, unsafe ORM methods, and dynamic identifiers. Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/sqli-results.md. Use when asked to find SQLi or database injection bugs.
sast-xxe
Detect XML External Entity (XXE) vulnerabilities in a codebase using a three-phase approach: recon (find XML parsing sites without external-entity hardening), batched verify (trace user input to each site in parallel subagents, 3 sites each), and merge (consolidate batch results). Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/xxe-results.md. Use when asked to find XXE or XML injection bugs.
sast-fileupload
Detect insecure file upload vulnerabilities in a codebase using a three-phase approach: discovery (find all upload sites), batched verify (check extension bypass and related issues in parallel subagents, 3 sites each), and merge (consolidate batch results). Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/fileupload-results.md. Use when asked to find file upload, unrestricted upload, or extension bypass bugs.
sast-jwt
Detect insecure JWT (JSON Web Token) implementations in a codebase using a two-phase approach: first map all JWT issuance and verification sites to understand the token lifecycle and signing configuration, then check each verification site for exploitable weaknesses such as algorithm confusion, missing signature verification, weak secrets, header injection, and missing claim validation. Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/jwt-results.md. If no JWT usage is found in Phase 1, Phase 2 is skipped. Use when asked to find JWT, token forgery, or authentication bypass bugs.
sast-ssti
Detect Server-Side Template Injection (SSTI) vulnerabilities in a codebase using a three-phase approach: recon (find template rendering sites that use dynamic strings), batched verify (trace user input to those sites in parallel subagents, 3 candidates each), and merge (consolidate batch results). Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/ssti-results.md. Use when asked to find SSTI or template injection bugs.
sast-hardcodedsecrets
Detect hardcoded sensitive data (API keys, access tokens, private keys, passwords, etc.) in publicly accessible code — frontend JavaScript, mobile apps, client-side bundles, and HTML templates. Uses a three-phase approach: recon (find secret candidates), batched verify (confirm real secrets in public code paths, 3 candidates each), and merge (consolidate batch results). Requires sast/architecture.md (run sast-analysis first). Outputs findings to sast/hardcodedsecrets-results.md. Use when asked to find hardcoded secrets, leaked API keys, or exposed credentials.
Didn't find tool you were looking for?