F-Secure Virus Descriptions : Warpigs.B
| NAME: | Warpigs.B |
| ALIAS: | W32/Warpigs.B, W32/Warpi.worm, W32.HLLW.Warpigs.B |
Warpigs.B is a network worm with an IRC backdoor and self-updating
capabilities. Warpigs.B was written in Visual C++ and it spreads
in UPX packed form with the size of around 67KB.
Network spreading
Warpigs.B contains a really long password list with more than
1600 entries.
The worm uses these when scanning for vulnerable hosts. If any of the
passwords gives access to the victim the worm copies itself there.
Warpigs.B has a copy of the psexec.exe tool in its body. Psexec is
used to copy and run the worm on vulnerable hosts.
System infection
When Warpigs.B enters a system it copies itself to the System Directory
as 'winupdate.exe'. It add references to this copy in the registry as
'HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\windowsupdate'
and
'HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\windowsupdate'
The infected copy is also added to system.ini as
[Boot]
Shell=explorer winupdate.exe
With these modifications the worm makes sure that it will be
started everytime the computer is started.
When scanning for vulnerable remote systems the worm drops a UPX
packed copy the popular network tool psexec.exe. This file is
dropped to the System Directory as 'pqonwe.exe'.
Backdoor
Warpigs.B is built around an IRC controlled backdoor component. The backdoor
provides a remote attacker with full control over the infected machine.
When the worm is started the backdoor component connects to a predefined
IRC channel. The IRC server this worm uses listens on port 5000 instead
of the usual 6667 like other IRC servers.
The backdoor has a command for updating the worm from a predefined
website. The website is not reachable at this point anymore.
Removal
F-Secure has created a special disinfection tool for this worm.
F-Warpigs kills the running copy of the worm from the memory,
removes the infected files and reverts the configuration changes the
worm had made.
The F-Warpigs tool is available for download from
ftp://ftp.f-secure.com/anti-virus/tools/f-warpigs.zip
Detection
Detection of the Warpigs.B worm is available in the following
FSAV update:
[FSAV_Database_Version]
Version=2003-07-23_03
[Analysis: Gergely Erdelyi; F-Secure Corporation; July 23rd, 2003]
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