WORM_OTORUN.FN
Worm:Win32/Autorun.YY (Microsoft); W32/Worm-FCG!DCF321DA462C (McAfee); W32.Virut.CF (Symantec); Worm.VBS.Autorun.ht (Kaspersky); Trojan.Win32.Generic.pak!cobra (Sunbelt); Found Luhe.Fiha.B (AVG)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It disables Task Manager, Registry Editor, and Folder Options.
TECHNICAL DETAILS
410,368 bytes
EXE
Yes
31 May 2013
Arrival Details
This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
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\Run
Lao Antivirus = "%Windows%\NOTEPAD.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"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
HKEY_CLASSES_ROOT\.sm2
HKEY_CLASSES_ROOT\sm2File\DefaultIcon
HKEY_CLASSES_ROOT\sm2File\shell\
open\command
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
JITDebug = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Window Title = "9"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
jpegfile
InfoTip = "Size: 7.24 MB"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{645FF040-5081-101B-9F08-00AA002F954E}
LocalizedString = "Recycle Bin"
(Note: The default value data of the said registry entry is {random values}.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
InfoTip = "Size: 2.56 MB"
(Note: The default value data of the said registry entry is prop:FileDescription;Company;FileVersion;Create;Size.)
It creates the following registry entry(ies) to disable Task Manager, Registry Tools and Folder Options:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Explorer = "%System%\Explorer.sm2"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoRun = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
This report is generated via an automated analysis system.
SOLUTION
9.300
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Identify and delete files detected as WORM_OTORUN.FN using either the Startup Disk or Recovery Console
Step 3
Enable Registry Editor, Task Manager, and Folder options
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_CURRENT_USER\Software\Microsoft\Windows Script
- Settings
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
- Run
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
- System
- In HKEY_CLASSES_ROOT
- .sm2
- In HKEY_CLASSES_ROOT\sm2File
- DefaultIcon
- In HKEY_CLASSES_ROOT\sm2File\shell\open
- command
Step 5
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\Run
- Lao Antivirus = "%Windows%\NOTEPAD.EXE"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows Script\Settings
- JITDebug = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- Window Title = "9"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\jpegfile
- InfoTip = "Size: 7.24 MB"
Step 6
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{645FF040-5081-101B-9F08-00AA002F954E}
- From: LocalizedString = "Recycle Bin"
To: LocalizedString = ""{random values}""
- From: LocalizedString = "Recycle Bin"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "1"
To: HideFileExt = ""1""
- From: HideFileExt = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
- From: InfoTip = "Size: 2.56 MB"
To: InfoTip = ""prop:FileDescription;Company;FileVersion;Create;Size""
- From: InfoTip = "Size: 2.56 MB"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "explorer.exe"
To: Shell = ""Explorer.exe""
- From: Shell = "explorer.exe"
Step 7
Scan your computer with your Trend Micro product to delete files detected as WORM_OTORUN.FN. 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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