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Showing posts with label psexec. Show all posts
Showing posts with label psexec. Show all posts

Tuesday, October 29, 2013

Network Forensics with Tshark: Psexec intrusion

I love Tshark for network forensics; I think the command line version of Wireshark can be really efficient if it used wisely to detect a big amount of anomalies/attacks in our network. Let's see the next case.

The internal server (192.168.1.130/24) of a certain organization has been compromised several times. The fact that the server is not accessible from the outside led us to think that an internal user had also been compromised, and the attacker was doing "pivoting" from that machine to the server. Another option was that an infected USB had been the root of the problem. However, after checking that the firewall did not filter the traffic DMZ ---> Internal Network, we could confirm that this was the origin of the intrusion. The web server (192.168.20.1/24) in the DMZ was compromised, and from here the attacker could access the internal LAN using the Administrator account. To do this the attacker used Mimikatz to get the credentials of that machine and then ran Psexec against the internal server with the Administrator account.