WORM_UTOTI.DAM
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
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.
Installation
This worm drops the following copies of itself into the affected system:
- %User Temp%\svchost.com
It creates the following folders:
- %User Temp%\$RECYCLE.BIN
- %User Temp%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
- %User Temp%\scr
- %User Profile%\Templates\cache
- %User Profile%\cache\$RECYCLE.BIN
- %User Profile%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
- %System Root%\$RECYCLE.BIN
- %System Root%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
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
HotKey = "%User Profile%\cache\SFCsrvc.pif"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
HotKey = "%User Profile%\cache\SFCsrvc.pif"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
User Agent = "%System%\fdisk.com"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
User Agent = "%User Temp%\svchost.com"
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 %System%\fdisk.com"
(Note: The default value data of the said registry entry is Explorer.exe.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "%System%\userinit.exe,%System%\fdisk.com"
(Note: The default value data of the said registry entry is %Windows%\system32\userinit.exe,.)
Other System Modifications
This worm adds the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
System
HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows\System
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
regedit.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
mmc.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
msconfig.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
USBGUARD.EXE
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
VPTRAY.EXE
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
AVGNT.EXE
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
AVP.EXE
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
pctsgui.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
pctstray.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ashdisp.exe
HKEY_CURRENT_USER\SOFTWARE\vlad
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\System
DisableGPO = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
regedit.exe
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
mmc.exe
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
msconfig.exe
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
USBGUARD.EXE
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
VPTRAY.EXE
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
AVGNT.EXE
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
AVP.EXE
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
pctsgui.exe
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
pctstray.exe
debugger = "notepad"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
ashdisp.exe
debugger = "notepad"
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
run = "%User Temp%\svchost.com"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyServer = ":8181"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
LocalProxy = ":8181"
HKEY_CURRENT_USER\Software\vlad
iminf = "2.0.0.27"
It modifies the following registry entries:
HKEY_CURRENT_USER\Control Panel\Desktop
SCRNSAVE.EXE = "%User Temp%\scr\logon.exe"
(Note: The default value data of the said registry entry is %Windows%\system32\logon.scr.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Windows
load = "%User Temp%\svchost.com"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "2"
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"
(Note: The default value data of the said registry entry is 2.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = "1"
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
NofolderOptions = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableTaskMgr = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
System
DisableRegistryTools = "1"
Dropping Routine
This worm drops the following files:
- %User Temp%\scr\logon.exe
- %User Temp%\scr\data.scr
- %User Profile%\cache\SFCsrvc.pif
- %System%\fdisk.com
- %Common Startup%\sndvol32.exe
- %User Startup%\sndvol32.exe
- %System Root%\Thumbs.db
Other Details
This worm connects to the following possibly malicious URL:
- http://https.{BLOCKED}h.cx/Files/dcb
- http://https.{BLOCKED}h.cx/Files/test.tits
This report is generated via an automated analysis system.
SOLUTION
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_UTOTI.DAM 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\CurrentVersion\policies
- System
- In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows
- System
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- regedit.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- mmc.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- msconfig.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- USBGUARD.EXE
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- VPTRAY.EXE
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- AVGNT.EXE
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- AVP.EXE
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- pctsgui.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- pctstray.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
- ashdisp.exe
- In HKEY_CURRENT_USER\SOFTWARE
- vlad
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
- HotKey = "%User Profile%\cache\SFCsrvc.pif"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- HotKey = "%User Profile%\cache\SFCsrvc.pif"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- User Agent = "%System%\fdisk.com"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- User Agent = "%User Temp%\svchost.com"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\System
- DisableGPO = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\regedit.exe
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\mmc.exe
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\msconfig.exe
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\USBGUARD.EXE
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\VPTRAY.EXE
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AVGNT.EXE
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AVP.EXE
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\pctsgui.exe
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\pctstray.exe
- debugger = "notepad"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ashdisp.exe
- debugger = "notepad"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- run = "%User Temp%\svchost.com"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- ShowSuperHidden = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- ProxyServer = ":8181"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
- LocalProxy = ":8181"
- In HKEY_CURRENT_USER\Software\vlad
- iminf = "2.0.0.27"
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_CURRENT_USER\Control Panel\Desktop
- From: SCRNSAVE.EXE = "%User Temp%\scr\logon.exe"
To: SCRNSAVE.EXE = ""%Windows%\system32\logon.scr""
- From: SCRNSAVE.EXE = "%User Temp%\scr\logon.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows
- load = "%User Temp%\svchost.com"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: HideFileExt = "2"
To: HideFileExt = ""1""
- From: HideFileExt = "2"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = "2"
To: Hidden = ""2""
- From: Hidden = "2"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
- ProxyEnable = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "explorer.exe %System%\fdisk.com"
To: Shell = ""Explorer.exe""
- From: Shell = "explorer.exe %System%\fdisk.com"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Userinit = "%System%\userinit.exe,%System%\fdisk.com"
To: Userinit = ""%Windows%\system32\userinit.exe,""
- From: Userinit = "%System%\userinit.exe,%System%\fdisk.com"
Step 7
Search and delete these components
- %User Temp%\scr\logon.exe
- %User Temp%\scr\data.scr
- %User Profile%\cache\SFCsrvc.pif
- %System%\fdisk.com
- %Common Startup%\sndvol32.exe
- %User Startup%\sndvol32.exe
- %System Root%\Thumbs.db
Step 8
Search and delete these folders
- %User Temp%\$RECYCLE.BIN
- %User Temp%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
- %User Temp%\scr
- %User Profile%\Templates\cache
- %User Profile%\cache\$RECYCLE.BIN
- %User Profile%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
- %System Root%\$RECYCLE.BIN
- %System Root%\$RECYCLE.BIN\{5F229C11-5039-40E4-8537-6950BB1C9ECC}
Step 9
Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.DAM. 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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