WORM_DELF.CML
N/A
Windows
Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.
As of this writing, the said sites are inaccessible.
TECHNICAL DETAILS
Arrival Details
This Worm 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 copies of itself into the affected system:
- %Application Data%\Virtual Disk Service\vds.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 creates the following folders:
- %Application Data%\Virtual Disk Service
(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 uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.
Autostart Technique
This Worm drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\vds.lnk - shortcut of the dropped copy (vds.exe)
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)
Propagation
This Worm searches for folders in all physical and removable drives then drops copies of itself inside the folder as {folder name}.EXE.
Download Routine
This Worm accesses the following websites to download files:
- http://{BLOCKED}eak.{BLOCKED}nkiller.com/config.css
- http://http///plugin/{BLOCKED}.{BLOCKED}/update/myapp.zip
- http://http///plugin/{BLOCKED}.{BLOCKED}/plugin/sndm.zip
It saves the files it downloads using the following names:
- %User Temp%\config.css
- %User Temp%\myapp.zip
- %User Temp%\sndm.zip
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)
As of this writing, the said sites are inaccessible.
Other Details
This Worm does the following:
- It sets the attributes of the folders to Hidden to trick the user into clicking the malware copy.
- It waits for the user's actions in the affected machine. If the user opens a file location with folders in it, then it will proceed with its propagation routine.
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
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_DELF.CML
- 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 folders
Step 5
Search and delete these files
- %User Startup%\vds.lnk
- %User Temp%\config.css
- %User Temp%\myapp.zip
- %User Temp%\sndm.zip
Step 6
Scan your computer with your Trend Micro product to delete files detected as WORM_DELF.CML. 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 the following Trend Micro Support pages for more information:
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