Exchange

11 Jul 2018

Passing-the-Hash to NTLM Authenticated Web Applications

This article details a Pass-the-Hash (PtH) attack technique against web applications using Windows NTLM authentication. The attack allows impersonation of domain users by injecting a user's NT hash to authenticate to web applications without knowing the actual password. A practical demonstration is provided using an Exchange 2013 server and Mimikatz to execute the attack.

William Knowles
22 Sep 2017

"Tasking" Office 365 for Cobalt Strike C2

A novel Command and Control (C2) technique for Cobalt Strike was demonstrated using Office 365's Exchange Web Services. The technique leverages Outlook tasks as a communication channel to transmit malicious traffic through a legitimate service. The proof-of-concept shows how attackers can use the External C2 interface to create covert communication paths through enterprise collaboration tools.

David Chismon
7 Oct 2016

Accessing Internal Fileshares through Exchange ActiveSync

Exchange ActiveSync (EAS) can be exploited to access internal Windows file shares using only user mailbox credentials. The vulnerability was confirmed in Exchange 2013 and 2016 with near-default configurations. Attackers can list file share contents and download files by using specific EAS commands, potentially bypassing traditional access controls.