DOS and Open Redirect with user input
### Impact
A redirect vulnerability in the `fastify-static` module allows remote attackers to redirect Mozilla Firefox users to arbitrary websites via a double slash `//` followed by a domain: `http://localhost:3000//a//youtube.com/%2e%2e%2f%2e%2e`.
A DOS vulnerability is possible if the URL contains invalid characters `curl --path-as-is "
http://localhost:3000//^/.."`
The issue shows up on all the `fastify-static` applications that set `redirect: true` option. By default, it is `false`.
### Patches
The issue has been patched in `fastify-static@4.4.1`
### Workarounds
If updating is not an option, you can sanitize the input URLs using the `rewriteUrl`
https://www.fastify.io/docs/latest/Server/#rewriteurl server option.
### References
+ Bug founder: drstrnegth
+ hackerone Report
https://hackerone.com/reports/1361804
### For more information
If you have any questions or comments about this advisory:
* Open an issue in fastify-static
https://github.com/fastify/fastify-static
* Contact the security team
https://github.com/fastify/fastify/blob/main/SECURITY.md#the-fastify-security-team