WORM_DORKBOT.AZA
Trojan.Win32.Jorik.IRCbot.qwh (Kaspersky), Backdoor.IRCBot (Sunbelt), TR/Jorik.IRCbot.qwh (Antivir)
Windows 2000, Windows XP, Windows Server 2003
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 then deletes itself afterward.
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
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 file name}.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 executes then deletes itself afterward.
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}
shellexecute=RECYCLER\{random characters}.exe
;{garbage}
shell\open\command=RECYCLER\{random characters}.exe
;{garbage}
icon=shell32.dll,7
;{garbage}
action=Open folder to view files
;{garbage}
shell\explore\command=RECYCLER\{random characters}.exe
;{garbage}
useautoplay=1
;{garbage}
Other Details
This worm connects to the following URL(s) to get the affected system's IP address:
- http://api.wipmania.com/
It connects to the following possibly malicious URL:
- http://pps.{BLOCKED}n.net
- http://p.{BLOCKED}n.net
- http://k.{BLOCKED}n.net
NOTES:
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
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
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} = "%User Profile%\Application Data\{random file name}.exe"
- {random file name} = "%User Profile%\Application Data\{random file name}.exe"
Step 4
Search and delete this folder
- {removable drive letter}:\RECYCLER
Step 5
Search and delete this file
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
- {removable drive letter}:\{folder name}.lnk
Step 6
Search and delete AUTORUN.INF files created by WORM_DORKBOT.AZA that contain these 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
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DORKBOT.AZA. 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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