FirstBlood-#628Reflected XSS on Login.php goto parameter
This issue was discovered on FirstBlood v2.0.0 (issues patched)



On 2021-10-26, sumyth Level 2 reported:

Hi,

Please find a brief description of the vulnerability below,

Summary

On the login.php page on firstblood.com, there exists a reflected XSS vulnerability which can be used to execute arbitrary JavaScript payloads.

Steps to Reproduce:

  1. Visit the vulnerable endpoint. Add the 'goto=' parameter to the URL along with payload and send the request to server.

  1. Enter a valid username/password combo and click on 'secure login'. Observe that the server responds back with JavaScript payload getting executed in the next page.

Impact

Reflected XSS present in the GET parameter of login URL can allow an attacker to run malicious JavaScript on victim's browser which can lead to unintended re-directs, phishing attacks etc.

P3 Medium

Endpoint: login.php

Parameter: goto

Payload: javascript:confirm%25%32%38document.location%25%32%39;


FirstBlood ID: 39
Vulnerability Type: Reflective XSS

Our mistake: The parameter "goto" on login.php should of been "fixed" when redirecting to prevent XSS but due to an oversight from Sean and Karl, the new code did not make it into production. This has since updated since the event ended and you're recommended to re-try. It's related to bug ID 26 because the idea was developers fixed *this* one (when redirecting) but forgot the other reflection.