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SANS ISC: Print Bomb? (Take 2) - SANS Internet Storm Center SANS ISC InfoSec Forums

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Print Bomb? (Take 2)

A week ago we mentioned a "print bomb" malware specimen doing the rounds, with a gradually improving AV detection ratio. However, we are receiving reports (Thanks Conor!) with variants of what looks like the same malware, with a very reduced AV detection ratio (0/37), so do not relax your defenses.

Virus Total:

This new sample, called "xpsp4ress.dll", is stored on C:\Windows\System32 and creates a scheduled task in Windows with what seems to be a random name (e.g. "UUSCPK"), running "C:\WINDOWS\system32\rundll32.exe 'C:\WINDOWS\system32\xpsp4ress.dll' ". Then it seems to propagate looking for share folders and/or printers (sometimes the DLL or EXE ends up in the spool queue and as a result reproduces the observed garbage printing behavior).

Some of the domains that has been identified when the malware phones home (C&C) are:

  • hxxp://
  • hxxp://
  • hxxp://
  • hxxp://

Look for them in your logs. There is a related write up available from Symantec:

The beauty of this unexpected malware behavior is that it can easily be detected throughout the organization printers and print servers, although at the expense of wasting precious paper, and trees as a consequence. Let's save the planet! ... and don't forget this is a good opportunity to evaluate the security of your printing architecture (network isolation, access controls, printer management, etc).

Raul Siles
Founder and Senior Security Analyst with Taddong

Raul Siles

152 Posts
Jun 21st 2012
Hey There, that link looks wrong, did you mean instead.
Thanks, it has been fixed.
Raul Siles

152 Posts
Just posted
Raul Siles
1 Posts
One thing that they are not mentioning is that in the /printers folder you will have two files for the malicious job. The SPL file which is the malware, and there is a SDH file that will actually contain the userID of the infected user. So if you are seeing a lot of machines firing off the alerts look at the SDH file to find the infected user.
Raul Siles
2 Posts
July 2, 2012 - "... we came across a new -worm- that causes the garbage print jobs. Symantec detects this worm as W32.Printlove. W32.Printlove uses the Microsoft Windows Print Spooler Service Remote Code Execution Vulnerability (CVE 2010-2729)* discovered in 2010 to spread across networks. We have created a video..."
MS10-061 - Critical
- - 9.3 (HIGH)
Last revised: 07/19/2011 - "... as exploited in the wild in September 2010, aka 'Print Spooler Service Impersonation Vulnerability'."

160 Posts

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