WORM_DORKBOT.CA
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This worm arrives via removable drives. It may be dropped by other malware.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It also has rootkit capabilities, which enables it to hide its processes and files from the user.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It may be dropped by other malware.
It may be downloaded from the following remote sites:
- http://{BLOCKED}e.com/dl/133427805/4e64adb/b1.dat
- http://{BLOCKED}7.hotfile.com/get/5734caeab7c19f1f61af2c2efbaa844650c3a74f/4eaa2a70/2/4e0c5cda66f98382/7f3f25d/b1.dat
Installation
This worm drops the following copies of itself into the affected system:
- %User Profile%\Application Data\{random characters}.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
{malware file name} = "%User Profile%\Application Data\{malware file name}.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 characters}.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}
action=Open folder to view files
;{garbage}
icon=shell32.dll,7
;{garbage}
useautoplay=1
;{garabage}
shellexecute=RECYCLER\{random characters}.exe
;{garbage}
shell\open\command=RECYCLER\{random characters}.exe
;{garbage}
Rootkit Capabilities
This worm also has rootkit capabilities, which enables it to hide its processes and files from the user.
Download Routine
This worm downloads an updated copy of itself from the following website(s):
- http://{BLOCKED}e.com/dl/133427805/4e64adb/b1.dat
- http://{BLOCKED}7.hotfile.com/get/5734caeab7c19f1f61af2c2efbaa844650c3a74f/4eaa2a70/2/4e0c5cda66f98382/7f3f25d/b1.dat
Other Details
This worm connects to the following URL(s) to get the affected system's IP address:
- http://api.wipmania.com/
SOLUTION
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.CA
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
- {malware file name} = "%User Profile%\Application Data\{malware file name}.exe"
- {malware file name} = "%User Profile%\Application Data\{malware file name}.exe"
Step 5
Search and delete this folder
Step 6
Search and delete AUTORUN.INF files created by WORM_DORKBOT.CA that contain these strings
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.CA. 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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