Request To Outbound Fetch
Untrusted request input flows into an outbound HTTP/URL fetch (HttpClient / WebRequest / WebClient), enabling Server-Side Request Forgery (CWE-918).
Standards mapping
- OWASP Top 10
- A10:2021 - Server-Side Request Forgery (SSRF)
- OWASP ASVS
- V12.6.1 (L1)
Vulnerable vs. safe
var resp = await httpClient.GetAsync(target);var resp = await httpClient.GetAsync("https://api.example.com/health");Why it matters & how to fix it
Untrusted request input flows into an outbound HTTP/URL fetch (HttpClient / WebRequest / WebClient), enabling Server-Side Request Forgery (CWE-918). An attacker can pivot to internal services and cloud metadata endpoints. Validate the target against a strict allow-list of hosts/schemes, resolve and re-check the address, and block link-local/private ranges.
References
Rule ID integsec.csharp.ssrf.request-to-outbound-fetch - engine: Opengrep - license: MIT - Copyright (c) IntegSec Inc.
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Start a pentestRelated checks
- JavaScript / TypeScript - SSRF & Path TraversalPath Join With Request
- JavaScript / TypeScript - SSRF & Path TraversalPath Traversal Tainted Input
- JavaScript / TypeScript - SSRF & Path TraversalSSRF Outbound Request Tainted Input
- Python - SSRF & Path TraversalPath Traversal
- Python - SSRF & Path TraversalSSRF HTTP Request
- Java - SSRF & Path TraversalPath Traversal Tainted Input