F-Secure Virus Descriptions : Bugbear.L
[Summary] | [Detailed Description] | [Detection]
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| NAME: | Bugbear.L |
| ALIAS: | I-Worm.Tanatos.k, W32/Bugbear.L@mm, W32/Bugbear.L |
The Bugbear.L (also known as Tanatos.k) worm appeared on
September 1st, 2004. The worm spreads itself as an attachment
in e-mail messages.
The worm has a backdoor and terminates security software. The
backdoor can be instructed to drop a TCP proxy application.
The worm's body is a Windows PE executable file compressed with the
UPX executable compressor. The unpacked body is around 128 KiB and
was written in Microsoft Visual C++.
System Infection
When the worm's file is run, it copies itself to Windows System
Folder a random name and creates a startup key for this file
in the Registry:
[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"<randomname>" = "%SystemDir%\<randomname>.exe"
Bugbear.L keeps the collected email addresses and other data in
scrambled files with random names in the System Folder.
%SystemDir% represents the Windows System folder name, for
example C:\Windows\System32 on Windows XP systems.
Email Propagation
To gather email addresses Bugbear.L searches through files that have
the following strings in their name:
.SHT
.TXT
.ASP
.HTM
.ODS
INBOX
.MMF
.NCH
.MBX
.EML
.TBB
.DBX
Using its own SMTP engine Bugbear.L sends emails to the collected
addresses. Sender of the mails is spoofed and the content is
randomly chosen from the following components:
Email subjects:
Greets!
!!! WARNING !!!
Hi!
sexy
good news!
Re:
Your Gift
Sex pictures
I cannot forget you!
Fwd:
News
You are fat!
Love
Warning!
photo
Friendly
new reading
;)
I love you!
Is that your password?
photos
empty account
Old photos
Me nude
fantastic
wow!
bad news
Lost n Found
New Contests
Today Only
[Fwd: look] ;-)
Greetings!
Report
Please Help...
Stats
I need photo!!!
Interesting...
Introduction
various
Announcement
history screen
look
Just a reminder
Payment notices
hmm..
update
Hello!
Email bodies:
Take a look to the attachment
See the attached file for more info
Please see Attachment
Pease open an attachment to see the message.
see attachment
See the attached file
please,read the attach file.
Attachment file names which come in ZIP files:
readme.txt[lots-of-spaces].scr
love.jpg[lots-of-spaces].scr
you.jpg[lots-of-spaces].scr
myphoto.jpg[lots-of-spaces].scr
news.doc[lots-of-spaces].scr
image.jpg[lots-of-spaces].scr
message.txt[lots-of-spaces].scr
pic.jpg[lots-of-spaces].scr
girls.jpg[lots-of-spaces].scr
photo.jpg[lots-of-spaces].scr
video.avi[lots-of-spaces].scr
music.mp3[lots-of-spaces].scr
song.wav[lots-of-spaces].scr
a000032.jpg[lots-of-spaces].scr
aol.com
bellsouth.net
bigpond.com
bluewin.ch
btinternet.com
btopenworld.com
earthlink.net
freesurf.ch
usa.com
microsoft.com
hotmail.com
ntlworld.com
excite.com
worldnet.att.net
msn.com
yahoo.com
The worm avoids spreading to e-mail addresses that contain any of
the following:
remove
spam
undisclosed
recipients
noreply
lyris
virus
trojan
mailer-daemon
postmaster@
root@
nobody@
localhost
localdomain
list
talk
ticket
majordom
Backdoor
Bugbear.L starts a thread that listens on port 1080 where the
remote attacker can connect and control the compromised
computer. The backdoor component is very similar to the one
found in Bugbear.B. For more information see the Bugbear.B
description:
http://www.f-secure.com/v-descs/bugbear_b.shtml
Through the backdoor the worm can be instructed to drop a TCP
proxy program that allows the attacker to initiate connections
through the compromised computer. This component listens on
port 5010/TCP.
The proxy is copied to the Windows System Folder as kernel32s.exe
and added to the registry:
[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
"Kernel32" = "%SystemDir%\kernel32s.exe"
Termination of Security Software
Bugbear.L periodically enumerates all running processes and terminates
all that are on this list:
_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
Detection for Bugbear.L worm was published on September 1st, 2004 in
the following F-Secure Anti-Virus updates:
[FSAV_Database_Version]
Version=2004-09-01_02
Technical Details:
Gergely Erdelyi, September 1st, 2004;
F-Secure Corporation
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