PE_SQUIRREL.A
Virus:Win32/Squirrel.A (Microsoft); W32/Squirrel (McAfee); W32.Squirrel (Symantec); Virus.Win32.Squirrel.a (Kaspersky); BehavesLike.Win32.Malware.sfm (mx-v) (Sunbelt); Win32/Squirrel.A (AVG)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: File infector
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This file infector arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This file infector 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 file infector registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\DBGV
Other System Modifications
This file infector adds the following registry keys:
HKEY_CURRENT_USER\Software\Sysinternals\
DbgView
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DBGV
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DBGV
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DBGV
Start = "3"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DBGV
ImagePath = "\??\%System Root%\Dbgv.sys"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\DBGV
ImagePath = "\??\%System%\Drivers\Dbgv.sys"
It deletes the following registry keys:
HKEY_CURRENT_USER\Software\Systems Internals\
DbgView
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\Dbgv\Enum
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\Dbgv\Security
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\Dbgv
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\DBGV\Enum
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\DBGV\Security
Dropping Routine
This file infector drops the following files:
- %System%\Drivers\Dbgv.sys
(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)
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
Restart in Safe Mode
Step 3
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\System\CurrentControlSet\Services
- DBGV
- In HKEY_CURRENT_USER\Software\Sysinternals
- DbgView
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\SYSTEM\ControlSet001\Services\DBGV
- Type = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DBGV
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DBGV
- Start = "3"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DBGV
- ImagePath = "\??\%System Root%\Dbgv.sys"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\DBGV
- ImagePath = "\??\%System%\Drivers\Dbgv.sys"
Step 5
Search and delete this file
- %System%\Drivers\Dbgv.sys
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_SQUIRREL.A. 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.
Step 7
Restore these deleted registry keys/values from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- In HKEY_CURRENT_USER\Software\Systems Internals
- DbgView
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Dbgv
- Enum
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Dbgv
- Security
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
- Dbgv
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DBGV
- Enum
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DBGV
- Security
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