FRISK Software International


Summary of W32/Bugbear.B@mm
Alias:I-Worm.Tanatos.b
Length: 72.192 bytes
Infectable objects: Win32 Executables (.EXE)
Discovered: 5 Jun 2003
Definition files: 5 Jun 2003
Risk Level: Low
Distribution:Low
Infection Method:Mass-mailing and file infecting
Payload: Infected systems can be compromised using the backdoor capability of the worm
 
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Brief description
Technical description
Removal Instructions

Brief Description

Like it's predecessor (Bugbear.A@mm) Bugbear.B@mm is a UPX packed mass-mailing worm with process termination, keylogging and backdoor capabilities, but where the A variant left off Bugbear.B@mm continues as being polymorphic and an fileinfector which targets certain commonly used programs.

The worm also contains a large list of domain names registered to banks, which it uses to determine if the infected system is inside one of those domains. Like the A variant it contains a list of applications belonging to popular Anti-Virus, Firewalls and other security related programs and terminates them if found running on an infected system.



Technical Description

The worm's file is a Windows PE executable file compressed with UPX file compressor and encrypted with a simple cryptoalgorithm that changes in every worm generation making the worm polymorphic. The packed worm's file size is 72192 bytes, the unpacked size is over 170 kilobytes.

Installation to system

When the worm's file is run, it installs itself to system by infecting files of several popular applications and system tools. The following files in Program Files and Windows folders are infected:

%ProgramFilesDir%\winzip\winzip32.exe
%ProgramFilesDir%\kazaa\kazaa.exe
%ProgramFilesDir%\ICQ\Icq.exe
%ProgramFilesDir%\DAP\DAP.exe
%ProgramFilesDir%\Winamp\winamp.exe
%ProgramFilesDir%\AIM95\aim.exe
%ProgramFilesDir%\Lavasoft\Ad-aware 6\Ad-aware.exe
%ProgramFilesDir%\Trillian\Trillian.exe
%ProgramFilesDir%\Zone Labs\ZoneAlarm\ZoneAlarm.exe
%ProgramFilesDir%\StreamCast\Morpheus\Morpheus.exe
%ProgramFilesDir%\QuickTime\QuickTimePlayer.exe
%ProgramFilesDir%\WS_FTP\WS_FTP95.exe
%ProgramFilesDir%\MSN Messenger\msnmsgr.exe
%ProgramFilesDir%\ACDSee32\ACDSee32.exe
%ProgramFilesDir%\Adobe\Acrobat 4.0\Reader\AcroRd32.exe
%ProgramFilesDir%\CuteFTP\cutftp32.exe
%ProgramFilesDir%\Far\Far.exe
%ProgramFilesDir%\Outlook Express\msimn.exe
%ProgramFilesDir%\Real\RealPlayer\realplay.exe
%ProgramFilesDir%\Windows Media Player\mplayer2.exe
%ProgramFilesDir%\WinRAR\WinRAR.exe
%ProgramFilesDir%\adobe\acrobat 5.0\reader\acrord32.exe
%ProgramFilesDir%\Internet Explorer\iexplore.exe
%WinDir%\winhelp.exe
%WinDir%\notepad.exe
%WinDir%\hh.exe
%WinDir%\mplayer.exe
%WinDir%\regedit.exe
%WinDir%\scandskw.exe

where %ProgramFilesDir% is a Program Files directory and %WinDir% is Windows directory.

The worm can also drop its file to Startup folder with a random name or as SETUP.EXE, so it will be activated on next system restart. Additionally the worm drops a keylogging component in Windows System directory with a random name and DLL extension. The name can be MGLKCKK.DLL for example. Also the worm creates 2 additional files in Windows System folder where it stores its data in encrypted form.

Spreading in e-mails

The worm spreads in e-mail messages. It has its own SMTP engine. To find e-mail addresses the worm looks for files with the following names and extensions:

.ODS
.MMF
.NCH
.MBX
.EML
.TBB
.DBX
INBOX

Some of such files are e-mail databases and they contain a lot of e-mail addresses. The worm sends itself to all found addresses. However, it avoids sending itself to e-mail addresses containing any of the following:

remove
spam
undisclosed
recipients
noreply
lyris
virus
trojan
mailer-daemon
postmaster@
root@
nobody@
localhost
localdomain
list
talk
ticket
majordom

The subject of an infected message is either taken from random files on an infected computer or selected from the following list:

Greets!
Get 8 FREE issues - no risk!
Hi!
Your News Alert
$150 FREE Bonus!
Re:
Your Gift
New bonus in your cash account
Tools For Your Online Business
Daily Email Reminder
News
free shipping!
its easy
Warning!
SCAM alert!!!
Sponsors needed
new reading
CALL FOR INFORMATION!
25 merchants and rising
Cows
My eBay ads
empty account
Market Update Report
click on this!
fantastic
wow!
bad news
Lost & Found
New Contests
Today Only
Get a FREE gift!
Membership Confirmation
Report
Please Help...
Stats
I need help about script!!!
Interesting...
Introduction
various
Announcement
history screen
Correction of errors
Just a reminder
Payment notices
hmm..
update
Hello!

The body of an infected message can be empty or it can contain a text from a random file on an infected comuter. The body of an infected message can contain I-Frame exploit. It allows the worm to run automatically on some computers when an infected e-mail is viewed (for example, with Outlook and IE 5.0 or 5.01). This vulnerability is fixed and a patch for it is available on Microsoft site:

The attachment name can be SETUP.EXE or it can contain one of the following strings:

readme
Setup
Card
Docs
news
image
images
pics
resume
photo
video
music
song
data

The worm can also "borrow" a name from a random file on an infected computer. The extension of an infected attachment is selected from the following list:

exe scr pif

In case the worm used a file's name from an infected computer, the worm's attachment can have 2 or more extensions, for example DOCUMENT.DOC.EXE . The worm checks the extension of the file it borrows the name from and sets the content type of its attachment in an infected message accordingly.

Extensions the worm checks:

reg
ini
bat
h
diz
txt
cpp
c
html
htm
jpeg
jpg
gif
cpl
dll
vxd
sys
com
exe
bmp

Worm's attachment content types:

image/gif
image/jpeg
application/octet-stream
text/plain
text/html

The worm fakes sender's e-mail address, so if you receive an infected message please do not reply to it as it will most likely go to a person whose computer is not infected by the worm.

Please note that Bugbear.B worm can send out corrupted attachments that will not run. Such attachments are usually shorter than the original worm's file.

Spreading in local network

The worm has the ability to infect remote computers over a local network. It waits for some time before starting its infection cycle and then enumerates network shares, connects to them and tries to infect the following files in Program Files and Windows folders on remote computers:

%ProgramFilesDir%\winzip\winzip32.exe
%ProgramFilesDir%\kazaa\kazaa.exe
%ProgramFilesDir%\ICQ\Icq.exe
%ProgramFilesDir%\DAP\DAP.exe
%ProgramFilesDir%\Winamp\winamp.exe
%ProgramFilesDir%\AIM95\aim.exe
%ProgramFilesDir%\Lavasoft\Ad-aware 6\Ad-aware.exe
%ProgramFilesDir%\Trillian\Trillian.exe
%ProgramFilesDir%\Zone Labs\ZoneAlarm\ZoneAlarm.exe
%ProgramFilesDir%\StreamCast\Morpheus\Morpheus.exe
%ProgramFilesDir%\QuickTime\QuickTimePlayer.exe
%ProgramFilesDir%\WS_FTP\WS_FTP95.exe
%ProgramFilesDir%\MSN Messenger\msnmsgr.exe
%ProgramFilesDir%\ACDSee32\ACDSee32.exe
%ProgramFilesDir%\Adobe\Acrobat 4.0\Reader\AcroRd32.exe
%ProgramFilesDir%\CuteFTP\cutftp32.exe
%ProgramFilesDir%\Far\Far.exe
%ProgramFilesDir%\Outlook Express\msimn.exe
%ProgramFilesDir%\Real\RealPlayer\realplay.exe
%ProgramFilesDir%\Windows Media Player\mplayer2.exe
%ProgramFilesDir%\WinRAR\WinRAR.exe
%ProgramFilesDir%\adobe\acrobat 5.0\reader\acrord32.exe
%ProgramFilesDir%\Internet Explorer\iexplore.exe
%WinDir%\winhelp.exe
%WinDir%\notepad.exe
%WinDir%\hh.exe
%WinDir%\mplayer.exe
%WinDir%\regedit.exe
%WinDir%\scandskw.exe

where %ProgramFilesDir% is a Program Files directory and %WinDir% is Windows directory.

Also the worm tries to locate common startup folder on remote computers and copies itself there as SETUP.EXE or with a random name and .EXE extension.

As a result remote computers will become infected either after restart or after a user there runs an infected file.

Killing processes

W32/Bugbear.B@mm kills the following processes

_AVP32.EXE
_AVPCC.EXE
_AVPM.EXE
ACKWIN32.EXE
ANTI-TROJAN.EXE
APVXDWIN.EXE
AUTODOWN.EXE
AVCONSOL.EXE
AVE32.EXE
AVGCTRL.EXE
AVKSERV.EXE
AVNT.EXE
AVP.EXE
AVP32.EXE
AVPCC.EXE
AVPDOS32.EXE
AVPM.EXE
AVPTC32.EXE
AVPUPD.EXE
AVSCHED32.EXE
AVWIN95.EXE
AVWUPD32.EXE
BLACKD.EXE
BLACKICE.EXE
CFIADMIN.EXE
CFIAUDIT.EXE
CFINET.EXE
CFINET32.EXE
CLAW95.EXE
CLAW95CF.EXE
CLEANER.EXE
CLEANER3.EXE
DVP95.EXE
DVP95_0.EXE
ECENGINE.EXE
ESAFE.EXE
ESPWATCH.EXE
F-AGNT95.EXE
F-PROT.EXE
F-PROT95.EXE
F-STOPW.EXE
FINDVIRU.EXE
FP-WIN.EXE
FPROT.EXE
FRW.EXE
IAMAPP.EXE
IAMSERV.EXE
IBMASN.EXE
IBMAVSP.EXE
ICLOAD95.EXE
ICLOADNT.EXE
ICMON.EXE
ICSUPP95.EXE
ICSUPPNT.EXE
IFACE.EXE
IOMON98.EXE
JEDI.EXE
LOCKDOWN2000.EXE
LOOKOUT.EXE
LUALL.EXE
MOOLIVE.EXE
MPFTRAY.EXE
N32SCANW.EXE
NAVAPW32.EXE
NAVLU32.EXE
NAVNT.EXE
NAVW32.EXE
NAVWNT.EXE
NISUM.EXE
NMAIN.EXE
NORMIST.EXE
NUPGRADE.EXE
NVC95.EXE
OUTPOST.EXE
PADMIN.EXE
PAVCL.EXE
PAVSCHED.EXE
PAVW.EXE
PCCWIN98.EXE
PCFWALLICON.EXE
PERSFW.EXE
RAV7.EXE
RAV7WIN.EXE
RESCUE.EXE
SAFEWEB.EXE
SCAN32.EXE
SCAN95.EXE
SCANPM.EXE
SCRSCAN.EXE
SERV95.EXE
SMC.EXE
SPHINX.EXE
SWEEP95.EXE
TBSCAN.EXE
TCA.EXE
TDS2-98.EXE
TDS2-NT.EXE
VET95.EXE
VETTRAY.EXE
VSCAN40.EXE
VSECOMR.EXE
VSHWIN32.EXE
VSSTAT.EXE
WEBSCANX.EXE
WFINDV32.EXE
ZONEALARM.EXE

The worm has separate process killing routines for Windows 9x and Windows NT-based operating systems.

Backdoor component

The worm has a backdoor component similar to the one used in its previous version. The backdoor listens to TCP port 1080 for commands from a remote host. A hacker can connect to the backdoor and perform the following action:

  • get information about infected computer
  • upload and download files
  • start files
  • delete files
  • terminate processes
  • get process list
  • start keylogger
  • start HTTP server on a selected port

The Bugbear.B worm's backdoor does not use secure authentication like its previous variant, so the backdoor can be used by many hackers, not just the worm's author.

Affecting bank computers

The worm has a large list of domains belonging mostly to banks. At startup the worm checks the domain name of an infected computer and then compares it to the its internal list. If the domain name matches, the worm can enable AutoDial feature on an infected computer by modifying the following Registry key:

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings] "EnableAutodial"=dword:00000001

This is done to keep infected banks' workstations always on-line, so the backdoor component could be accessible all the time after infection. This makes easier for a hacker to use a keylogger and other backdoor features to steal sensitive information. Such actions make banks' computers more vulnerable than other infected computers.

The list of bank domains that the worm has includes banks from many different countries: France, UK, Germany, Australia, Italy, Greece, Denmark, New Zealand, Spain, Brasil, Romania, Poland, Argentina, Switzerland, Finland, Taiwan, Turkey, Iceland, Slovakia, Korea, USA, South Africa, Baltic Republics, Austria, Hungary, Norway, Czech Republic and some other countries.

Side Effect

According to reports, network printers start to print a lot of garbage when the worm spreads in a network. This might be the side-effect of the worm's attempts to infect a network.



Removal Instructions

First of all you need to update your virus signature files.

If you have Windows 95/98/ME please follow these instructions.

If you have Windows NT/2000/XPplease follow these instructions.

For users running Windows ME or XP, please click here more information.


[Technical Description: F-Secure Anti-Virus Research Team; F-Secure Corp.; June 5th-6th, 2003]
 


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