WORM_TATERF.AW
Worm:Win32/Taterf (Microsoft); Mal/Taterf-B (Sophos)
Windows
Threat Type: Worm
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Propagates via removable drives, Dropped by other malware
This Worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
As of this writing, the said sites are inaccessible.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
104,764 bytes
EXE
Yes
03 Jul 2018
Drops files, Connects to URLs/IPs, Deletes files
Arrival Details
This Worm arrives via removable drives.
It 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 component file(s):
- %User Temp%\4tddfwq0.dll
- %System%\drivers\cdaudio.sys
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It drops the following copies of itself into the affected system:
- %User Temp%\xvassdf.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
Autostart Technique
This Worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
54dfsger = "%User Temp%\xvassdf.exe"
Other System Modifications
This Worm deletes the following files:
- %System%\drivers\cdaudio.sys (replaced by malware with its component)
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Security
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
It adds the following registry entries as part of its installation routine:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
Start = "4"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
ImagePath = "\??\%System%\drivers\cdaudio.sys"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys
DisplayName = "AVPsys"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Security
Security = "{random hex values}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
Count = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
NextInstance = "1"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AVPsys\Enum
0 = Root\LEGACY_AVPSYS\0000
It modifies the following registry entries:
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
ShowSuperHidden = "0"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"
(Note: The default value data of the said registry entry is 1.)
Propagation
This Worm drops the following copy of itself in all physical and removable drives:
- {Drive Letter}:\8d.bat
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:
[AutoRun]
open=8d.bat
shell\open\Command=8d.bat
Download Routine
This Worm accesses the following websites to download files:
- http://{BLOCKED}.{BLOCKED}/1rb/ar1.rar
As of this writing, the said sites are inaccessible.
Other Details
This Worm deletes the initially executed copy of itself
SOLUTION
9.300
6.350.21
09 Aug 2009
6.351.00
10 Aug 2009
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
Identify and delete files detected as WORM_TATERF.AW using either the Startup Disk or Recovery Console
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- 54dfsger = %User Temp%\xvassdf.exe
- 54dfsger = %User Temp%\xvassdf.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 = 2
To: Hidden = 1
- From: Hidden = 2
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 0
To: ShowSuperHidden = 1
- From: ShowSuperHidden = 0
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
- From: CheckedValue = 0
To: CheckedValue = 1
- From: CheckedValue = 0
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\SYSTEM\CurrentControlSet\Services
- AVPsys
- AVPsys
Step 7
Search and delete AUTORUN.INF files created by WORM_TATERF.AW that contain these strings
- [AutoRun]
- open=8d.bat
- shell\open\Command=8d.bat
Step 8
Restore these deleted files from backup
*Note: Only Microsoft-related keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
- %System%\drivers\cdaudio.sys
Step 9
Scan your computer with your Trend Micro product to delete files detected as WORM_TATERF.AW. 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 the following Trend Micro Support pages for more information:
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