WORM_OTORUN.EO
Windows 2000, XP, Server 2003

Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Copies itself in all available logical drives, Propagates via flashdrives
This worm drops copies of itself into all the removable drives connected to an affected system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It modifies certain registry entries to hide Hidden files.
TECHNICAL DETAILS
610620 bytes
PE
Yes
08 Mar 2011
Drops files
Installation
This worm drops the following files:
- %system%\autorun.i
- %system%\autorun.in
It drops the following copies of itself into the affected system:
- %system%\csrcs.exe
Autostart Technique
This worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = %system%\csrcs.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
csrcs = %system%\csrcs.exe
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = Explorer.exe csrcs.exe
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
Propagation
This worm drops copies of itself into all the removable drives connected to an affected system.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:
- [autorun]
- open={random}.exe
- action=view files
- shell\open\command={random}.exe
- useautoplay=1
- icon=%system%\shell32.dll,7
- shell\open\default=1
- action=@{random}.exe
Other Details
This worm modifies the following registry entries to hide Hidden files:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
SOLUTION
8.900
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
Terminate a process file/s detected as WORM_OTORUN.EO
*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- csrcs = %system%\csrcs.exe
- csrcs = %system%\csrcs.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
- csrcs = %system%\csrcs.exe
- csrcs = %system%\csrcs.exe
Step 4
Restore this modified 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\Explorer\Advanced
- From: Hidden = 2
To: Hidden = 1
- From: Hidden = 2
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: SuperHidden = 0
To: SuperHidden = 1
- From: SuperHidden = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 0
To: ShowSuperHidden = 1
- From: ShowSuperHidden = 0
Step 5
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.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM\amty RESTOREStep 6
Search and delete AUTORUN.INF files created by WORM_OTORUN.EO that contain these strings
open={random}.exe
action=view files
shell\open\command={random}.exe
useautoplay=1
icon=%system%\shell32.dll,7
shell\open\default=1
action=@{random}.exe
Step 7
Search and delete this file
%System%\autorun.in
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_OTORUN.EO. 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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