U.S Army Infected by Worm

Wired reports that the U.S Army network is under assault by a variant of the SillyFDC worm called Agent-BTZ [1]. In order to restrain the infection, the U.S. Strategic Command has ban the use of every portable media on its network, this include USB keys, CDs, flash cards, floppies etc… Both the SIPRNet and NIPRNet are affected by this directive.

The SillyFDC worm infects systems through replication, i.e. by copying itself to various locations such as these folders[2]:

  • %System%
  • %Windir%
  • %Temp%
  • %UserProfile%
  • %ProgramFiles%
  • %SystemDrive%
  • %CommonProgramFiles%
  • %CurrentFolder%

Computer Virus Looming
Computer Virus Looming

It will also try to copy itself to any drive connected to the machine by scanning drives A:\ to Z:\, which is why the U.S Army is banning the use of portable media for the time being.  According to F-Secure who first discovered the worm[3], the variant in question will also create these files[4]:

  • %windir%\system32\muxbde40.dll
  • %windir%\system32\winview.ocx
  • %temp%\6D73776D706461742E746C62FA.tmp
  • %windir%\system32\mswmpdat.tlb

It will then install itself into the registry to make sure the worm starts every time the computer is booted. It will also attempt to download a JPG file from http://worldnews.ath.cx/update/img0008/[REMOVED].jpg and create an AUTORUN.INF file on each drive on the computer, which contains the following:

shell\open\Command=rundll32.exe .\\[RANDOM].dll,InstallM

[RANDOM] is a randomly generated filename for the malicious DLL. Each time a new partition or a new drive is plugged in, Agent.BTZ will infect it immediately.

The SillyFDC worm doesn’t have any payload, as it only replicates itself through systems it finds using physical medias only. But its variant, the Agent.BTZ is a known Trojan dropper. A dropper is the kind of Trojan that will look to download and execute other malware. It’s surprising that it found its way into the U.S Army network. So that might be a tip for any worm/Trojan writer: add physical media replication to your malware like in the good ol’ days before e-mail, as it seems sending it by e-mail or click jacking is pretty well filtered in military networks, but peripherals such as USB keys are still often used by personnel. And this will surely open the eyes of the network admins of the U.S Army: scan anything plugged into the network.

Also, Graham Cluley, senior technology consultant at Sophos advises:

“… that users disable the autorun facility of Windows so removable devices such as USB keys and CD ROMs do not automatically launch when they are attached to a PC”

With whom I agree.


Since so many people asked me about this worm, I looked deeply into Internet and found this code, which seems to be part of the script of the Silly FDC worm (that’s the best I could do for now). This script basically copy files from one directory to another, renames the core of the worm and put it into another directory and add registry keys. I cannot confirm this as I found this on an Indonesian blog, so if anyone can look into this, please let me know. Thank you. Blog : http://morphians.wordpress.com/category/uncategorized/

See also:

“US Army bans USB devices to contain worm”, John Leyden, The Register, November 20, 2008, http://www.theregister.co.uk/2008/11/20/us_army_usb_ban/ (accessed on November 20, 2008)

[1] “Under Worm Assault, Military Bans Disks, USB Drives”, Noah Shachtman, Danger Room, Wired, http://blog.wired.com/defense/2008/11/army-bans-usb-d.html (accessed on November 20, 2008)

[2] “W32.SillyFDC”, Symantec, http://securityresponse.symantec.com/security_response/writeup.jsp?docid=2006-071111-0646-99&tabid=1 (accessed on November 20, 2008)

[3] “Troj/Agent-EMB”, Sophos, http://www.sophos.com/security/analyses/viruses-and-spyware/trojagentemb.html (accessed on November 20, 2008)

[4] “F-Secure Malware Information Pages: Worm:W32/Agent.BTZ”, F-Secure Corporation, http://www.f-secure.com/v-descs/worm_w32_agent_btz.shtml (accessed on November 20, 2008)

Author: Jonathan Racicot

INTJ, goa trance, RE, python, malware, wine, books, french bulldogs, genetics, biohacking, CtF, night owl, transhumanist, AI, machines, cyber ops.

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