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 [email protected]

Workarounds

If updating is not an option, you can sanitize the input URLs using the rewriteUrl server option.

References

• Bug founder: drstrnegth
• hackerone Report

For more information

If you have any questions or comments about this advisory:

• Open an issue in fastify-static
• Contact the security team