# MA-037.112001: MyCERT Advisory - W32.Badtrans.B@MM Worm

**Date:** 29 Oct 2001  
**Source:** https://www.mycert.org.my/portal/advisory?id=MA-037.112001  
**Advisory ID:** MA-037.112001

---

1.0 Description
#### 1.1 Overview
The W32.Badtrans.B@MM is a memory resident worm and is a variant of W32.Badtrans.A@mm was discovered on November 24 2001. It propagates via MAPI32, has a key logger component and arrive with randomly selected double-extension filenames. It also creates the file \Windows\System\Kdll.dll. It uses functions from this file to log keystrokes.It does not require the email receiver to open the attachment for it to execute. It uses a known vulnerability (http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.asp) in Internet Explorer-based email clients, Microsoft Outlook and Microsoft Outlook Express to automatically execute the file attachment.
The risk assessment by many anti-virus vendors, for this worm has been graded to a MEDIUM risk to corporate users and High for home users. This is because the worm can be stopped at corporate gateways and mail servers and the fact that home users tend to update their anti-virus files less frequently and often do not have VirusScan configured to scan compressed files which is required for detection. Thus home users are strictly advised to take preventive measures against this worm.
#### 1.2 Systems Affected
Microsoft Internet Explorer 5.01 and 5.5 based email clients, Microsoft Outlook and Microsoft Outlook Express.
**Note**: Internet Explorer 5.01 Service Pack 2 and Internet Explorer 6.0 are not vulnerable.
#### 1.3 Limitation
1.3.1 No limitation. It does not require the email receiver to open the attachment for it to execute.
#### 1.4 Aliases
The worm is also known as:
- W32/Badtrans-B, BADTRANS.B,
W32/Badtrans@MM
W32.Badtrans.B@mm, W32/BadTrans.B-mm
**1.5 Payload**
1.5.1 Sending emails out to large numbers of people. This is usually done by accessing a local address book and sending emails to a certain number of people within that address book.
1.5.2 Attempt to gain access to passwords or other system-level security settings. It might also search for openings in the Internet processing components of the computer to install a program on that system that could be controlled remotely by someone over the Internet. The worm installs keystroke logging Trojan horse.
### 2.0 Technical Matters
#### 2.1 Functionality (as extracted from Symantec)
This worm arrives as an email with one of several attachment names and a combination of two appended extensions. It contains a set of bits that control its behaviour:
- 001 Log every window text
002 Encrypt keylog
004 Send log file to one of its addresses
008 Send cached passwords
010 Shut down at specified time
020 Use copyname as registry name (else kernel32)
040 Use kernel32.exe as copyname
080 Use current filename as copypath (skips 100 check)
100 Copy to %system% (else copy to %windows%)
When it is first executed, it copies itself to %System% or %Windows% as Kernel32.exe, based on the control bits. Then it registers itself as a service process (Windows 9x/Me only). It creates the key log file \%System%\Cp\_25389.nls and drops %System%\Kdll.dll which contains the key logging code.
NOTE: %Windows% and %System% are variables. The worm locates the \Windows folder (by default this is C:\Windows or C:\Winnt) or the \System folder (by default this is C:\Windows\System or C:\Winnt\System32) and copies itself to that location.
A timer is used to examine the currently open window once per second, and to check for a window title that contains any of the following as the first three characters:
- LOG
PAS
REM
CON
TER
NET
These texts form the start of the words LOGon, PASsword, REMote, CONnection, TERminal, NETwork. There are also Cyrillic versions of these same words in the list. If any of these words are found, then the key logging is enabled for 60 seconds. Every 30 seconds, the log file and the cached passwords are sent to one of these addresses:
- [[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
[[email protected]](/cdn-cgi/l/email-protection)
After 20 seconds, the worm will shut down if the appropriate control bit is set.
If RAS support is present on the computer, then the worm will wait for an active RAS connection. When one is made, with a 33% chance, the worm will search for email addresses in \*.ht\* and \*.asp in %Personal% and Internet Explorer %Cache%. If it finds addresses in these files, then it will send mail to those addresses. The attachment name will be one of the following:
- Pics
images
README
New\_Napster\_Site
news\_doc
HAMSTER
YOU\_are\_FAT!
stuff
SETUP
Card
Me\_nude
Sorry\_about\_yesterday
info
docs
Humor
fun
In all cases, MAPI will also be used to find unread mail to which the worm will reply. The subject will be "Re:". In that case, the attachment name will be one of the following:
- PICS
IMAGES
README
New\_Napster\_Site
NEWS\_DOC
HAMSTER
YOU\_ARE\_FAT!
SEARCHURL
SETUP
CARD
ME\_NUDE
Sorry\_about\_yesterday
S3MSONG
DOCS
HUMOR
FUN
In all cases, the worm will append two extensions. The first will be one of the following:
- .doc
.mp3
.zip
The second extension that is appended to the file name is one of the following:
- .pif
.scr
The resulting file name would look similar to CARD.Doc.pif or NEWS\_DOC.mp3.scr.
If SMTP information can be found on the computer, then it will be used for the From: field. Otherwise, the From: field will be one of these:
- "Mary L. Adams"
"Monika Prado"
"Support"
" Admin"
" Administrator"
"JESSICA BENAVIDES"
"Joanna"
"Mon S"
"Linda"
" Andy"
"Kelly Andersen"
"Tina"
"Rita Tulliani"
"JUDY"
" Anna"
Email messages use the malformed MIME exploit to allow the attachment to execute in Microsoft Outlook without prompting. For information on this, go to:
- http://www.microsoft.com/technet/security/bulletin/MS01-020.asp
After sending mail, the worm adds the value
- Kernel32 kernel32.exe
to the registry key
- HKEY\_LOCAL\_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
This will run the worm the next time that you start Windows.
### 3.0 Possible Steps
#### 3.1 Prevention
3.1.1 Patch Internet Explorer 5.01 and 5.5. The patch is available at:
- http://www.microsoft.com/technet/security/bulletin/MS01-020.asp
3.1.2 DO NOT execute any attachment appended with email and do not open any email attachments with the extensions mentioned as in 2.1.
3.1.3 Do not open any suspicious/unknown attachments and delete them immediately. Regularly update the virus definition file of your antivirus software and run a virus scan on the computer. This is to ensure that the software is able to detect the presence of a new virus.
The list of known antivirus vendor can be found at:
- [https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=b83f4c4d-f1e2-4a9d-ab55-6389ae1f6efc](https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=b83f4c4d-f1e2-4a9d-ab55-6389ae1f6efc
)
3.1.3 Always run a virus scan on any downloadable files before executing it. It is advisable that your antivirus software is running in "Auto Protect Mode" at all time.
Refer to Safe Email Practices:
- [https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=96fa0022-2ca9-47cb-975f-0d1225cc278e](https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=96fa0022-2ca9-47cb-975f-0d1225cc278e
)
3.1.4 Large organisations are recommended to filter email attachments, block all email that have attachments with the extensions .scr and .pif.attachments. It is also recommended to scan email at the gateway for virus.
#### 3.2 Detection
Any antivirus with the latest virus definitions is able to detect the worm.To detect the virus, run an antivirus scan with the latest signature file on your system. Ensure the anti-virus is configured to scan ALL FILES, or if selected files, ensure the relevant extensions such as .PIF and .SCR are included.
#### 3.3 Removal
No fix tool has been developed yet to clean up this worm. Users need to follow the manual removals.
For Windows 95/98/Me
1. Restart Windows in Safe Mode.
2. Run anti-virus on your PC with latest virus definitions and enabled to scan all files.
List of anti-virus vendors is available at:
[https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=b83f4c4d-f1e2-4a9d-ab55-6389ae1f6efc](https://www.mycert.org.my/portal/articles-content?menu=4b05e0fb-afa1-408f-90ca-ea0edf4aca8b&id=b83f4c4d-f1e2-4a9d-ab55-6389ae1f6efc
)
Delete all files that are detected as W32.Badtrans.B@mm.
3. Remove the value that it added to the registry.
- Click Start, and click Run. The Run dialog box appears.
- Type regedit and then click OK. The Registry Editor opens.
- Navigate to the following key:
- HKEY\_LOCAL\_MACHINE\SOFTWARE\Microsoft\ Windows\CurrentVersion\RunOnce
- In the right pane, delete the following value:
- Kernel32 kernel32.exe
- Click Registry, and then click Exit.
For Windows NT/2000
1. Rename the file Kernel32.exe.
- Click Start, point to Find or Search, and click Files or Folders.
- Make sure that "Look in" is set to (C:) and that Include subfolders is checked.
- In the "Named" or "Search for..." box, type the following:
Kernel32.exe
CAUTION: Make sure that you type the full name as shown. You must rename the Kernel32.exe file, not the legitimate Windows file Kernel32.dll
- Click Find Now or Search Now.
- Right-click the file that is displayed and then click Rename.
- Rename the file to Kernel32.old and press Enter.
- Close the Find or Search window.
- Restart the computer.
2. Remove the value added to the registry.
- Click Start, and click Run. The Run dialog box appears.
- Type regedit and then click OK. The Registry Editor opens.
- Navigate to the following key:
HKEY\_LOCAL\_MACHINE\SOFTWARE\ Microsoft\Windows\CurrentVersion\RunOnce
- In the right pane, delete the following value:
Kernel32 kernel32.exe
- Click Registry, and then click Exit.
3. Restart the computer.
4. Run AntiVirus and delete all files that are detected as W32.Badtrans.B@mm.
### 4.0 More Information
More information on this virus can be obtained from the following sites:
4.1 McAfee
http://vil.nai.com/vil/content/v\_99069.htm
4.2 Symantec Antivirus Research Center
http://securityresponse.symantec.com/avcenter/venc/data/[[email protected]](/cdn-cgi/l/email-protection)
4.3 Trend Micro
http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM\_BADTRANS.B