WORM_VB.CVL
Worm:Win32/SillyFDC (Microsoft), W32/USBCasv (McAfee), W32.SillyFDC (Symantec), Win32/VB.FP worm (NOD32), Trojan.Win32.Generic!BT (Sunbelt)
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
93,612 bytes
EXE
Yes
02 Apr 2004
Arrival Details
This worm arrives by connecting affected removable drives to a system.
It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This worm drops the following files:
- %Windows%\uda.exe
- %System%\mswinsck.ocx
- %System%\Recycled\desktop.ini
(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 drops the following copies of itself into the affected system:
- %User Temp%\s.exe
- %System%\odbcasvc.exe
- %System%\Recycled\INFO.EXE
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %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.)
Autostart Technique
This worm registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\odbcasvc
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\Root\LEGACY_ODBCASVC
Other System Modifications
This worm adds the following registry entries:
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Policies\Exploer
NoDriveTypeAutoRun = "ff"
Propagation
This worm modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:
- [autorun]
- open=.\recycled\info.exe
- shell\1=S»++
- shell\1\Command=.\recycled\info.exe
- shellexecute=.\recycled\info.exe
NOTES:
It also drops the following AUTORUN.INF on the Windows system folder:
- %System%\autorun.inf
SOLUTION
9.200
4.384.03
02 Apr 2007
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
Restart in Safe Mode
Step 3
Delete this registry key
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- odbcasvc
- odbcasvc
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root
- LEGACY_ODBCASVC
- LEGACY_ODBCASVC
Step 4
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_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Policies\Exploer
- NoDriveTypeAutoRun = "ff"
- NoDriveTypeAutoRun = "ff"
Step 5
Search and delete AUTORUN.INF files created by WORM_VB.CVL that contain these strings
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_VB.CVL. 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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