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NTLMv2 Proxy Auth not working

Rodolpho | Last updated: Jul 20, 2017 01:20PM UTC

Hi, I'm trying to use burp proxy with a corporate proxy that requires NTLMv2, however it doesn't seem to be working. IE, Firefox and Chrome are working fine with it, but burp throws an error saying "Failed to connect to proxy server" when NTLM auth is turned on. The request from the proxy seems to bleed to the next request which is probably causing the issue. See tcp stream below: CONNECT www.google.com:443 HTTP/1.0 Host: www.google.com Proxy-Authorization: NTLM NTLMHASHHERE HTTP/1.1 407 Proxy Authentication Required Proxy-Authenticate: NTLM NTLMCHALLENGEHERE Cache-Control: no-cache Pragma: no-cache Content-Type: text/html; charset=utf-8 Proxy-Connection: Keep-Alive Connection: Keep-Alive Content-Length: 4344 <html> <!-- Header section --> <head><title>Warning: Access Denied</title><meta name="description" content="Access Denied"></head> <blockquote><body bgcolor="white"><center> <!-- End Header section --> <br>Please contact sup CONNECT www.google.com:443 HTTP/1.0 Host: www.google.com Proxy-Authorization: NTLM NTLMRESPONSEHERE port at email@corp.com for assistance</br> HTTP/1.1 200 Connection established

Liam, PortSwigger Agent | Last updated: Jul 20, 2017 01:37PM UTC

Hi Rodolpho Thanks for this report. We've confirmed this behaviour in the latest version of Burp Suite. As a workaround you can use Burp Suite 1.7.23. We are investigating this issue and will let you know when we have produced a fix.

PortSwigger Agent | Last updated: Jul 24, 2017 08:54AM UTC