In the end, he can use the authenticated session as he sees fit.įor such an attack to work, one needs to be in a man-in-the-middle position.

He extracts the NTLM authentication blobs from the client messages and puts them in modified messages to the server and vice versa. The attacker acts as a server to the client and as a client to the server. The diagram below gives a simplified view of NTLM relay attacks: It does not fix the lack of global integrity requirement for RPC. The solution implemented adds integrity requirement for the Task Scheduler Service. Microsoft released a fix as part of the Update Tuesday in May 2020.

This vulnerability was discovered by Compass Security in January 2020, disclosed to Microsoft Security Response Center and assigned CVE-2020-1113 as identifier. This attack was tested against a fully patched Windows Server 2016 Domain Controller. Provided the victim has administrative privileges on the target, the attacker can execute code on the remote target. CVE- 2020-1113ĭue to the absence of global integrity verification requirements for the RPC protocol, a man-in-the-middle attacker can relay his victim’s NTLM authentication to a target of his choice over the RPC protocol. In this article, we propose adding support for the RPC protocol to the already great ntlmrelayx from impacket and explore the new ways of compromise that it offers. Since a few years, we – as pentesters – (and probably bad guys as well) make use of NTLM relaying a lot for privilege escalation in Windows networks.

Lansweeper wmi access denied