WORM_TUFIK.AJ
Symantec: W32.Imaut.AS; Microsoft: Worm:Win32/VB.CB
Windows 2000, Windows XP, Windows Server 2003

Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.
It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.
It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names. The sent messages contains a link where a copy of the malware may be downloaded.
However, as of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This worm may be downloaded by other malware/grayware/spyware from remote sites.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This worm drops the following non-malicious files:
- %System%\Xpen.dat
- %System%\Penx.dat
- %Windows%\wininit.ini
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
It drops the following copies of itself into the affected system:
- %Windows%\dc.exe
- %Windows%\SVIQ.EXE
- %System%\WinSit.exe
- %System%\config\Win.exe
- %Windows%\system\Fun.exe
- %Windows%\inf\Other.exe
- %Windows%\Help\Other.exe
(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.
It injects threads into the following normal process(es):
- csrss.exe
- lsass.exe
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dc2k5 = "%Windows%\SVIQ.EXE"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Fun = "%Windows%\system\Fun.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
dc = "%Windows%\dc.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = "%System%\config\Win.exe"
It modifies the following registry entry(ies) to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%Windows%\inf\Other.exe"
(Note: The default value data of the said registry entry is "".)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe %System%\WinSit.exe"
(Note: The default value data of the said registry entry is "Explorer.exe".)
Propagation
This worm drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.
The sent messages contain the following link(s), where a copy of the malware may be downloaded:
- http://{BLOCKED}oivb.googlepages.com/NWB.txt
It sends copies of itself to target recipients using the following instant-messaging (IM) applications:
- Yahoo! Messenger
It sends the following messages using the aforementioned Instant Messaging applications:
Chuc mung, ban da tam thoi thoat khoi Worm DungCoi
http://{BLOCKED}ivb.googlepages.com/NWB.txt
Olalala, may tinh cua ban da dinh Worm DungCoi...........
Backdoor Routine
However, as of this writing, the said sites are inaccessible.
Other Details
This worm connects to the following possibly malicious URL:
- http://{BLOCKED}ivb.googlepages.com
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Identify and delete files detected as WORM_TUFIK.AJ using either the Startup Disk or Recovery Console
Step 3
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- dc2k5 = %Windows%\SVIQ.EXE
- dc2k5 = %Windows%\SVIQ.EXE
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- Fun = %Windows%\system\Fun.exe
- Fun = %Windows%\system\Fun.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- dc = %Windows%\dc.exe
- dc = %Windows%\dc.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- run = %System%\config\Win.exe
- run = %System%\config\Win.exe
Step 4
Restore this modified registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- From: load = %Windows%\inf\Other.exe
To:
- From: load = %Windows%\inf\Other.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = Explorer.exe %System%\WinSit.exe
To: Explorer.exe
- From: Shell = Explorer.exe %System%\WinSit.exe
Step 5
Search and delete this file
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_TUFIK.AJ. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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