NTLM authentication using Burp proxy

Hey buddies,

Just wanted to share my experience while doing an appsec for one of our clients.

I was doing appsec of an application which worked on NTLM authentication. With every request I was sending, the NTLM variables were queried and if authenticated I get a response.

After opening the browser, if I want to login to the application I have to provide my local domain password. This fetches the login page of the application where using my logins I can login to the application.

Here, I was struggling to setup a local proxy because whenever I setup a local proxy and send a new request, my NTLM variables were queried and I was not authenticated as local proxy has broken my NTLM authentication.

After struggling for some time, I found an option in BURP PROXY, under tab comms there is a check box asking for ‘do WWW authentication’. Basically we have to select this check box and select NTLM authentication here and provide the destination IP, Domain name, Domain password etc.

This way, working through BURP I solved the problem and continued the testing. But again remember that closing BURP removes this setting and you will have to again do the same settings to continue testing.

Cheers,
Prashant