Listen to this Post
The CVE-2023-XXXX vulnerability in Astro’s on-demand rendering mode stems from its insecure handling of the `X-Forwarded-Host` header. When a request is processed, Astro constructs the `Astro.url` object by directly using the value from the `X-Forwarded-Host` header if it is present, without any validation or sanitization. This occurs within the server-side adapter code, which parses incoming HTTP request headers to build the canonical URL for the application context. A malicious actor can send a crafted HTTP request containing a fraudulent `X-Forwarded-Host` header. Astro’s internal logic then blindly trusts this header value, reflecting it in the `Astro.url` properties such as `origin` and host. This flawed trust in an unvalidated, user-supplied header allows an attacker to manipulate the perceived origin of the request. When this manipulated `Astro.url` is used to generate links, canonical tags, or form actions, it can redirect users or leak sensitive data to a domain controlled by the attacker. The impact is severely amplified if the application is deployed behind a caching proxy, as the poisoned response containing the malicious host value can be cached and served to subsequent users.
Platform: Astro
Version: pre-2.0
Vulnerability : Header Injection
Severity: Critical
date: 2023-10-26
Prediction: 2023-11-16
What Undercode Say:
git clone https://github.com/Chisnet/minimal_dynamic_astro_server cd minimal_dynamic_astro_server nvm use yarn install yarn run build node ./dist/server/entry.mjs
curl --location 'http://localhost:4321/' --header 'X-Forwarded-Host: www.evil.com' --header 'Host: www.example.com'
How Exploit:
GET / HTTP/1.1 Host: www.example.com X-Forwarded-Host: www.evil.com
Protection from this CVE
Validate `X-Forwarded-Host` against an allowlist. Configure reverse proxies to strip unauthorized headers. Update Astro to a patched version.
Impact:
Cache Poisoning
Open Redirect
Credential Theft
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
