WORM_UTOTI.III
Windows 2000, XP, Server 2003

Threat Type: Worm
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Propagates via removable drives
This worm drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It deletes itself after execution.
TECHNICAL DETAILS
941,338 bytes
EXE
No
17 Nov 2010
Installation
This worm drops the following copies of itself into the affected system:
- %system%\csrcs.exe
It drops the following files:
- %system%\autorun.inf
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
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 modifies the following registry entries to hide files with Hidden attributes:
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.)
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- cydsfw.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:
;{garbage}
[AuTOrUn
;{garbage}
open=cydsfw.exe
;{garbage}
shell\open\Command=cydsfw.exe
;{garbage}
shell\open\Default=1
;{garbage}
Other Details
This worm deletes itself after execution.
NOTES:
The dropped AUTORUN.INF file is detected by Trend Micro as TROJ_OTORUN.SMJ.
SOLUTION
8.900
7.628.04
17 Nov 2010
11/17/2010 12:00:00 AM
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
Remove malware files dropped/downloaded by WORM_UTOTI.III
- TROJ_OTORUN.SMJ
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
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 = dword:00000002
To: Hidden = dword:00000001
- From: Hidden = dword:00000002
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: SuperHidden = dword:00000000
To: SuperHidden = dword:00000001
- From: SuperHidden = dword:00000000
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = dword:00000000
To: ShowSuperHidden = dword:00000001
- From: ShowSuperHidden = dword:00000000
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = Explorer.exe csrcs.exe
To: Shell = Explorer.exe
- From: Shell = Explorer.exe csrcs.exe
Step 5
Search and delete this file
Step 6
Search and delete AUTORUN.INF files created by WORM_UTOTI.III that contain these strings
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.III. 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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