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Dictionary/brute-force attack against "kerberized" IIS service accounts without triggering account lockout


From: "Ben Lincoln (F7EFC8C9 - FD)" <F7EFC8C9 () beneaththewaves net>
Date: Thu, 18 Dec 2014 21:00:15 -0800

Not sure if this is old news by now, but I haven't seen it mentioned anywhere.

I was writing some walkthroughs for the alpha version of Mimikatz 2.0, and realized that since the "Silver Ticket" functionality involves one of the Windows kerberos ticket encryption keys being the NTLM hash of the account which receives the kerberos ticket, it's possible to use it to check passwords for IIS application pool service accounts (if kerberos auth is used, of course), and this does not trigger an account lockout regardless of the number of attempts - at least not on Server 2012 RTM with the default settings (no "enhanced protection", etc.).

http://www.beneaththewaves.net/Projects/Mimikatz_20_-_Brute-Forcing_Service_Account_Passwords.html

Apologies in advance if this has already been discussed. This is definitely a POC-grade tool - I do not have the C/C++ skills to modify Mimikatz sufficiently to make this particular attack production-quality.

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