# ssrf

> Claude/Codex skill by [@thejefflarson](https://omgskills.com/library/thejefflarson/index.md) · 20 stars · Updated 2026-07-31

Detects HTTP requests to user-controlled URLs that can reach internal services or cloud metadata endpoints. Use when writing code that makes HTTP requests to URLs constructed from user input, fetches resources from caller-specified addresses, or proxies requests on behalf of users. Also invoke when implementing webhook receivers or URL preview features.

Tags: llms, security, skills

## Install

```sh
git clone https://github.com/thejefflarson/soundcheck /tmp/soundcheck && ln -s /tmp/soundcheck/.claude/skills/ssrf ~/.claude/skills/ssrf
```

## From README

SSRF Security Check (A10:2025 / API7:2023) What this checks Protects against Server-Side Request Forgery where an attacker tricks the server into making requests to internal services, cloud metadata endpoints, or arbitrary external hosts. Exploitation leads to internal network scanning, credential theft from cloud metadata APIs (169.254.169.254), and access to services behind firewalls. Vulnerable patterns Outbound HTTP fetch where the URL, host, or scheme comes from request input with no validation Webhook callback or URL-preview feature that follows whatever the caller supplies URL-fetch APIs that follow redirects by default, letting an allowlisted host 302 to an internal IP Hostname-only allowlists that do not also check the resolved IP — vulnerable to DNS rebinding Fix immediately Flag the vulnerable code, explain the risk, and suggest a fix establishing these properties.

## Links

- HTML page: https://omgskills.com/library/thejefflarson/soundcheck/dot-claude/skills/ssrf/
- GitHub: https://github.com/thejefflarson/soundcheck
- Author: [@thejefflarson](https://omgskills.com/library/thejefflarson/index.md)

## More from this repo

- [authentication-failures](https://omgskills.com/library/thejefflarson/soundcheck/dot-claude/skills/authentication-failures/index.md) — Detects weak password storage, flawed JWT validation, sessions surviving logout, and missing MFA in authentication code.
   - [@thejefflarson](https://omgskills.com/library/thejefflarson/index.md) · 20 stars
- [broken-access-control](https://omgskills.com/library/thejefflarson/soundcheck/dot-claude/skills/broken-access-control/index.md) — Detects missing ownership checks, broken role enforcement, and IDOR vulnerabilities that let users access other users'...
   - [@thejefflarson](https://omgskills.com/library/thejefflarson/index.md) · 20 stars
- [concurrency-correctness](https://omgskills.com/library/thejefflarson/soundcheck/dot-claude/skills/concurrency-correctness/index.md) — Detects multi-threaded code where a lock is held across a blocking operation, lock acquisition order risks deadlock,...
   - [@thejefflarson](https://omgskills.com/library/thejefflarson/index.md) · 20 stars