VBS_GUS.A
VBS/AutoRun.FS (ESET-NOD32); Worm:VBS/Gus.A (Microsoft)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Worm arrives via removable drives.
TECHNICAL DETAILS
Arrival Details
This Worm arrives via removable drives.
Installation
This Worm adds the following folders:
- %Windows%\Psy
- %Windows%\Spedssit
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It drops the following files:
- {Drive Letter}:\autorun.inf (Hidden Attribute, used to execute a file named ini12.vbs)
It drops the following copies of itself into the affected system:
- %Windows%\Psy\inyect12.vbs (Hidden Attribute)
- %Windows%\Spedssit\inyect12.vbs (Hidden Attribute)
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Autostart Technique
This Worm drops the following files:
- {Drive Letter}:\inyect.bat ← (Hidden Attribute, executes copy on the Drive Letter)
Other System Modifications
This Worm adds the following registry entries:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
Sstem = "%Windows%\Psy\guy.vbs"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckValue = 0
(Note: The default value data of the said registry entry is {user defined}.)
Propagation
This Worm drops the following copy of itself in all physical and removable drives:
- {Drive Letter}:\inyect12.vbs
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
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\Run
- Sstem = "%Windows%\Psy\guy.vbs"
- Sstem = "%Windows%\Psy\guy.vbs"
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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
- From: CheckValue = 0
To: CheckValue = {user defined}
- From: CheckValue = 0
Step 5
Search and delete this folder
- %Windows%\Psy
- %Windows%\Spedssit
Step 6
Search and delete these files
- {Drive Letter}:\inyect.bat
- {Drive Letter}:\autorun.inf
Step 7
Scan your computer with your Trend Micro product to delete files detected as VBS_GUS.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.
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