WORM_DORKBOT.AB
VirTool:Win32/VBInject (Microsoft), W32.IRCBot.NG (Symantec)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. 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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
It deletes itself after execution.
TECHNICAL DETAILS
286,720 bytes
EXE
Yes
04 Jul 2012
Arrival Details
This worm arrives via removable drives.
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:
- %User Profile%\Application Data\{random}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
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} = "%User Profile%\Application Data\{random}.exe"
Propagation
This worm creates the following folders in all removable drives:
- {Drive Letter}:\RECYCLER
It drops the following copy(ies) of itself in all removable drives:
- {Drive Letter}:\RECYCLER\{random}.exe
Download Routine
This worm connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}t.com/img/background.bmp
It saves the files it downloads using the following names:
- %User Profile%\Application Data\{random digit}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
Other Details
This worm connects to the following possibly malicious URL:
- http://api.{BLOCKED}ia.com/
- mxgame.{BLOCKED}8.org
- http://www.{BLOCKED}poli.it/images/8c319f7370b365e8.png
It deletes itself after execution.
NOTES:
This worm drops shortcuts pointing to its copy in all removable drives. These dropped shortcuts use the names of the folders located on the said drives for their file names.
SOLUTION
9.200
9.234.03
04 Jul 2012
9.235.00
05 Jul 2012
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Scan your computer with your Trend Micro product and note files detected as WORM_DORKBOT.AB
Step 3
Restart in Safe Mode
Step 4
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} = "%User Profile%\Application Data\{random}.exe"
- {random} = "%User Profile%\Application Data\{random}.exe"
Step 5
Search and delete this folder
- {Drive Letter}:\RECYCLER
Step 6
Search and delete this file
- {Drive Letter}:\{Folder Name}.lnk
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.AB. 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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