WORM_DORKBOT.MB
Worm:Win32/Dorkbot.A(Microsoft),Worm.Win32.Dorkbot(Sunbelt),Trojan.Generic.KDV.833887(Bitdefender),Win32/Dorkbot.B worm(Nod32)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
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.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
169,991 bytes
, EXE
Yes
27 Apr 2013
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 copies of itself into the affected system:
- %Application Data%\{Random File Name}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming 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 File Name} = "%Application%\{Random File Name}.exe"
Propagation
This worm creates the following folders in all removable drives:
- {Removable Drive}:\RECYCLER
It drops the following copy(ies) of itself in all removable drives:
- {Removable Drive}:\RECYCLER\{Random File Name}.exe
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]
{GARBAGE_CHARACTERS}
shellexecute=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
icon=shell32.dll,7
{GARBAGE_CHARACTERS}
shell\open\command=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
action=Open folder to view files
{GARBAGE_CHARACTERS}
shell\explore\command=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
useautoplay=1
Other Details
This worm connects to the following URL(s) to get the affected system's IP address:
- http://api.wipmania.com
It deletes the initially executed copy of itself
NOTES:
It drops the file {Removable Drive}:\RECYCLER\Desktop.ini to change the icon of the RECYCLER folder into the Recycle Bin icon.
It drops shortcut files pointing to the copy of itself in removable drives. These dropped .LNK files use the names of the folders located on the said drives for their file names. It then sets the attributes of the original folders to Hidden to trick the user into clicking the .LNK files.
SOLUTION
9.300
9.882.02
17 Jan 2013
9.883.00
18 Jan 2013
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 File Name} = "%Application%\{Random File Name}.exe"
- {Random File Name} = "%Application%\{Random File Name}.exe"
Step 4
Search and delete this folder
- {Removable Drive}:\RECYCLER
Step 5
Search and delete this file
- {Removable Drive}:\{Folder Name}.lnk
Step 6
Search and delete AUTORUN.INF files created by WORM_DORKBOT.MB that contain these strings
{GARBAGE_CHARACTERS}
shellexecute=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
icon=shell32.dll,7
{GARBAGE_CHARACTERS}
shell\open\command=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
action=Open folder to view files
{GARBAGE_CHARACTERS}
shell\explore\command=RECYCLER\{Random File Name}.exe
{GARBAGE_CHARACTERS}
useautoplay=1
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.MB. 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.
Did this description help? Tell us how we did.