WORM_VBNA.SMCE
W32.Changeup!gen9; Worm:Win32/Vobfus.gen!D; Trojan.Win32.VBKrypt.xnz; Downloader-CJX.gen.j; W32/SillyFDC-FI
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm drops copies of itself in all removable drives. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
TECHNICAL DETAILS
Installation
This worm drops the following copies of itself into the affected system:
- %User Profile%\{random filename}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
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
{random filename} = %User Profile%\{random filename}.exe
Other System Modifications
This worm modifies the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
Propagation
This worm drops copies of itself in all removable drives.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
The said .INF file contains the following strings:
{garbage characters}
[aUTOrUn]
{garbage characters}
ACTiON=Open folder and view files
{garbage characters}
shellexecute={random filename}.eXe
{garbage characters}
ICoN=%SysTeMRooT%\SystEM32\shEll32.DLl,4
{garbage characters}
Other Details
Based on analysis of the codes, it has the following capabilities:
- It drops .LNK files in removable drives that point to a copy of itself to automatically execute dropped copies when the drives are accessed. These .LNK files use random file names, names of the existing folders, and hardcoded file names. This is to execute the malware copy first before opening the real folder. It then changes the attributes of the original folders into Hidden and System to trick the users.
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
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
- {random filename} = %User Profile%\{random filename}.exe
- {random filename} = %User Profile%\{random filename}.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\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 0
To: 1
- From: ShowSuperHidden = 0
Step 5
Search and delete AUTORUN.INF files created by WORM_VBNA.SMCE that contain these strings
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_VBNA.SMCE. 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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