WORM_OTORUN.WSH
Worm:Win32/Rorpian (Microsoft); Worm.Win32.AutoRun.cewu (Kaspersky); W32/Autorun.worm.aabl (McAfee)
Windows 2000, Windows XP, Windows Server 2003

Threat Type: Worm
Destructiveness: No
Encrypted: No
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.
TECHNICAL DETAILS
Arrival Details
This worm arrives via removable drives.
It may be dropped by other malware.
Installation
This worm drops the following non-malicious file:
- %User Temp%\srv{random numbers}.ini
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)
It uses the following names for the copies it drops:
- %User Temp%\srv{random numbers}.tmp
(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp 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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\srv{Random Numners}\parameters
servicedll = "\?\globalroot\Device\HarddiskVolume1\%User Temp%\srv{random numbers}.tmp"
Other System Modifications
This worm adds the following registry entries as part of its installation routine:
HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
ProxyEnable = "0"
It adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Minimal\
srv{random numbers}
Propagation
This worm drops the following copy of itself in all physical and removable drives:
- setup{random numbers}.fon
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]
Action = Open folder to view files
rundll32.exe setup{random numbers}.fon
shell\open\command = rundll32.exe setup{random numbers}.fon
Icon = %System%\shell32.dll,4
useautoplay = 1
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Other Details
This worm connects to the following possibly malicious URL:
- http://{BLOCKED}.{BLOCKED}.88.10//srv
- http://{BLOCKED}.{BLOCKED}.88.10//dll
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
Identify and delete files detected as WORM_OTORUN.WSH using the Recovery Console
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_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- ProxyEnable = 0
Step 4
Delete this registry key
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal
- srv{random numbers}
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- srv{random numbers}
Step 5
Search and delete AUTORUN.INF files created by WORM_OTORUN.WSH that contain these strings
[AutoRun]
Action = Open folder to view files
rundll32.exe setup{random numbers}.fon
shell\open\command = rundll32.exe setup{random numbers}.fon
Icon = %System%\shell32.dll,4
useautoplay = 1
Step 6
Search and delete this file
- %User Temp%\srv{random numbers}.ini
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_OTORUN.WSH. 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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