WORM_VBNA.SMN
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This worm arrives via removable drives.
It 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
138,240 bytes
EXE
Yes
27 Jul 2010
Arrival Details
This worm arrives via removable drives.
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 string} = %User Profile%\{random filename}.exe
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:
[AutoRun]
Action=Open folder to view files
ShellExecute={random filename}.exe
Icon=%System%\shell32.DLL,4
UseAutoplay=1
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
Other Details
Based on analysis of the codes, it has the following capabilities:
- It drops .LNK files 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.
- It also drops the following file in all removable drives: zzz.dll - detected as WORM_VOBFUS.AI
SOLUTION
8.900
7.342.02
28 Jul 2010
7/28/2010 12:00:00 AM
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
Remove the malware/grayware file dropped/downloaded by WORM_VBNA.SMN
- WORM_VOBFUS.AI
Step 3
Scan your computer with your Trend Micro product and note files detected as WORM_VBNA.SMN
Step 4
Restart in Safe Mode
Step 5
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 string}=%User Profile%\{random filename}.exe
- {random string}=%User Profile%\{random filename}.exe
Step 6
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out 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 7
Scan your computer with your Trend Micro product to delete files detected as WORM_VBNA.SMN. 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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