> For the complete documentation index, see [llms.txt](https://dev-angelist.gitbook.io/writeups-and-walkthroughs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev-angelist.gitbook.io/writeups-and-walkthroughs/portswigger-web-security-academy/information-disclosure/common-sources-of-information-disclosure/authentication-bypass-via-information-disclosure.md). # Authentication bypass via information disclosure ## Description This lab's administration interface has an authentication bypass vulnerability, but it is impractical to exploit without knowledge of a custom HTTP header used by the front-end. To solve the lab, obtain the header name then use it to bypass the lab's authentication. Access the admin interface and delete the user `carlos`. You can log in to your own account using the following credentials: `wiener:peter` ## Solution

Starting access to wiener user Checking page sources there're not of interesting, so we can try access to admin page adding /admin path to our URL: and we can see this information disclosure message: "Admin interface only available to local users"

so, we start to analyze request for understanding more things

We can try to change request method to see if the answer changes. It will happen via TRACE method with the response status code 200.

Trace is a debug method and it display us an important information as: X-Custom-IP-Authorization: 37.101.171.137 We can copy it inserting a localhost IP: 127.0.0.1 in our request and change again method to GET

Now we're into admin panel having the permission to delete 'carlos' user

analyzing the reponse, there's a URL that permits to delete 'carlos' account: `GET /admin/delete?username=carlos`

Copy and add it into our request to delete account and solve the lab.