WORM_VRENAME.A
Windows
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Spammed via email, Propagates via network shares
This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives by accessing affected shared networks.
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
889,856 bytes
EXE
Yes
02 Feb 2015
Drops files
Arrival Details
This worm arrives as an attachment to email messages spammed by other malware/grayware or malicious users.
It arrives by accessing affected shared networks.
Installation
This worm drops the following copies of itself into the affected system:
- %Application Data%\Paint.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- Paint
Autostart Technique
This worm drops the following shortcut pointing to its copy in the User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\Paint.lnk
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)
Propagation
This worm drops copies of itself in the following drives:
- {Physical Drive Letter}:\Paint
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]
OPEN=Paint
icon=%SystemRoot%\system32\SHELL32.dll,4
open=Open
shell\open\command=Paint
NOTES:
It creates a copy of itself in folders in all physical drives with .exe files and uses it as its filename and rename the original file using this format v{Original Filename}.exe and sets its attributes to hidden.
It avoids folders in the %System Root% that belongs to the System.
When a mimic copy of this malware is executed, it will then execute the original file afterwards.
SOLUTION
9.700
11.442.05
26 Jan 2015
11.443.00
27 Jan 2015
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Identify and terminate files detected as WORM_VRENAME.A
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 4
Search and delete these files
- %User Startup%\Paint.lnk
Step 5
Search and delete AUTORUN.INF files created by WORM_VRENAME.A that contain these strings
- [autorun]
- OPEN=Paint
- icon=%SystemRoot%\system32\SHELL32.dll,4
- open=Open
- shell\open\command=Paint
Step 6
Scan your computer with your Trend Micro product to clean files detected as WORM_VRENAME.A. 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.
Step 7
Set system to display all hidden files and folders
Step 8
- Open a command prompt.
- For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Search box, type CMD then press Enter.
- For Windows Vista, Windows 7, and Windows Server 2008 users, click Start, type CMD in the Search input field then press Enter.
- For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower-left corner of the screen, click Command Prompt.
- In the CMD console, type the following:
ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][file name] [/S [/D] [/L]]
Where:
+ Sets an attribute.
- Clears an attribute
R Read-only file attribute
A Archive file attribute
S System file attribute
H Hidden file attribute
I Not content indexed file attribute
[drive:][path][filename]
Specifies a file or files for attrib to process
/S Processes matching files in the current folder and all subfolders.
/D Processes folders
/L Work on the attributes of the Symbolic Link versus the target of the Symbolic Link
Example:
To unhide all files and folders (including subfolders) in drive D:
ATTRIB –H D:\* /S /D
- Repeat Step 3 for folders and files in other drives or folders.
NOTES:
After scanning your computer to remove the dropped copies of this malware. To restore .EXE files that are renamed by this malware. Remove the prepend "v" character to the renamed .EXE files and remove its hidden attribute by following the steps stated above using ATTRIB.
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