WORM_OTORUN.GA
W32.Harakit (Symantec); Worm:AutoIt/Renocide.gen!E (Microsoft)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This worm arrives via removable drives.
It drops copies of itself in all removable drives. 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.
Installation
This worm drops the following copies of itself into the affected system:
- %System%\csrcs.exe
(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.)
It drops the following component file(s):
- %System%\autorun.inf - related to TROJ_OTORUN.SMJ
(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.)
It drops the following non-malicious files:
- %User Temp%\suicide.bat
- {drive letter}:\khq
(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 stays memory-resident by creating remote threads:
- csrcs.exe
Autostart Technique
This worm creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = %System%\csrcs.exe
Other System Modifications
This worm adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
It modifies the following registry entries:
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.)
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:
- dmouuc.exe
It drops copies of itself in all removable drives.
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 characters}
[AuTOrUn]
;{garbage characters}
open=dmouuc.exe
;{garbage characters}
shell\open\Command=dmouuc.exe
;{garbage characters}
shell\open\Default=1
;{garbage characters}
SOLUTION
Step 1
For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
- csrcs = %System%\csrcs.exe
- csrcs = %System%\csrcs.exe
Step 5
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 = 1
To: Hidden = 2
- From: Hidden = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: SuperHidden = 1
To: SuperHidden = 0
- From: SuperHidden = 1
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 1
To: ShowSuperHidden = 0
- From: ShowSuperHidden = 1
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = Explorer.exe
To: Shell = Explorer.exe csrcs.exe
- From: Shell = Explorer.exe
Step 6
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\SOFTWARE\Microsoft\DRM\
- amty
- amty
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\
- Run
- Run
Step 7
Search and delete AUTORUN.INF files created by WORM_OTORUN.GA that contain these strings
- ;{garbage characters}
[AuTOrUn]
;{garbage characters}
open=dmouuc.exe
;{garbage characters}
shell\open\Command=dmouuc.exe
;{garbage characters}
shell\open\Default=1
;{garbage characters}
Step 8
Search and delete these files
- %User Temp%\suicide.bat
- {drive letter}:\khq
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_OTORUN.GA 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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