Re: Compromised Windows Server

Hi Patrick

Came in this morning to find a windows 2003 server I manage scanning the
Internet for machines listening on tcp 139 and 445. While looking at the
machine I noticed the following processes running.


Sounds like you were able to capture some of the network traffic. Got any
packet dumps, netflows or the like?


I believe that the ponoas.exe is some sort of rootkit although searching on
google for this file name returns nothing. Also searching
mwvsta.exereturns nothing. At this point I have removed these files
from the system
and registry but am weary that the server will get hit again. Has anyone
had an experience with the following file or have any idea what rookkit of
virus they are associated with?

As other people have mentioned, file names a terribly unreliable way of
identifying malware. If you still have copies of the malware, run them
through virustotal (www.virustotal.com), this runs the files past a number
of AV scanners to see what they detect it as.

I'd also poke the malware to see how it wiggles.

You should be wary of the server being re-compromised. Especially if you
have not identified and corrected the vulnerability that was used to
compromise the server in the first place.

There's a number of things that I would recommend here - besides a complete
rebuild, which btw I normally recommend after any compromise:

1. Get a pen and piece of paper and start writing. :)

2. Run the MBSA tool (Microsoft Baseline Security Analyser) over the
server, this is good for a quick overview of missing patches for MS
products, record the results.

If the host is a web server, check for updates to php or whatever you
happen to be running there, record the results. For the record, you should
do this for every application which is reachable via the network on this
host, and if users browse the web from this server, every application
period. Record the results.

3. Run the MSRT (Malicious Software Removal Tool) over the affected host
and record the results.

4. Crank up any monitoring you do of traffic to/from this server to 11 for
a period which best reflects the requirements of your incident response
policy.

5. Write a report on your findings, and update your security/ response
procedures accordingly. If you don't have these procedures, then now is
a good time to get them. Nothing like a good compromise to get management
backing for this :).

5. If pain persists, contact the MSRC and your local CERT team.

AusCERT have a good document on responding to a compromise of a Windows
here: http://www.auscert.org.au/4323

The MSRT, and MBSA are all available free from Microsoft.

Hope that helps,

MacLeonard

--
MacLeonard Starkey, Security Analyst | Hotline: +61 7 3365 4417
AusCERT | Fax: +61 7 3365 7031
The University of Queensland | WWW: www.auscert.org.au
QLD 4072 Australia | Email: auscert@xxxxxxxxxxxxxx


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