Trojan.Win32.WUSUB.A
Trojan:Win32/Wusub.A (Microsoft)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
As of this writing, the said sites are inaccessible.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
167,936 bytes
Other
No
20 Feb 2019
Deletes files, Terminates processes, Connects to URLs/IPs
Arrival Details
This Trojan 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 Trojan drops the following files:
- %ProgramData%\TMPUSER.DAT - deleted afterwards.
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
It creates the following folders:
- %ProgramData%\Microsofts Help
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
It terminates itself if it finds the following processes in the affected system's memory:
- QHSAFETRAY.EXE
- QHWATCHDOG.EXE
- CMDAGENT.EXE
- CIS.EXE
- V3LITE.EXE
- SPIDERAGENT.EXE
- DWENGINE.EXE
- DWARKDAEMON.EXE
- BULLGUARDTRAY.EXE
- BDAGENT.EXE
- BULLGUARD.EXE
- BDSS.EXE
- BULLGUARD.EXE
- V3MAIN.EXE
- V3SP.EXE
- EGUI.EXE
- EKRN.EXE
Other System Modifications
This Trojan deletes the following files:
- %ProgramData%\AMMYY\wmihost.exe
- %ProgramData%\AMMYY\settings3.bin
- %ProgramData%\Foundation\wmites.exe
- %ProgramData%\Foundation\settings3.bin
- %ProgramData%\Foundation1\wmites.exe
- %ProgramData%\Foundation1\settings3.bin
- %ProgramData%\Microsoft\wsus.exe
- %ProgramData%\Microsoft\settings3.bin
- %ProgramData%\Microsofts Help\wsus.exe
- %ProgramData%\Microsofts Help\settings3.bin
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
It deletes the following folders:
- %ProgramData%\Settings
- %ProgramData%\Microsoft\Enc
- %ProgramData%\AMMYY
- %ProgramData%\Foundation
- %ProgramData%\Foundation1
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
Process Termination
This Trojan terminates the following processes if found running in the affected system's memory:
- wsus.exe
Download Routine
This Trojan connects to the following website(s) to download and execute a malicious file:
- http://{BLOCKED}.{BLOCKED}.209.169/dat1.omg
It saves the files it downloads using the following names:
- %ProgramData%\Microsofts Help\template_{hex string}.DATAHASH, which is decrypted and saved as %ProgramData%\Microsofts Help\wsus.exe
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
As of this writing, the said sites are inaccessible.
Other Details
This Trojan does the following:
- The file %ProgramData%\TMPUSER.DAT contains the output of executed command "net user /domain".
If the string "WORKGROUP" is present in the file, the malware is terminated. - It executes the following commands to stop and delete a service named "foundation":
- net.exe stop foundation
- sc delete foundation
- If running as an administrator, this malware registers the downloaded file as a service to ensure its automatic execution at every system startup by executing the following commands:
- sc create foundation binPath= "%ProgramData%\Microsofts Help\wsus.exe -service" type= own start= auto error= ignore
- net.exe start foundation y
- If running as a user, this malware adds the following registry entries and scheduled tasks to enable automatic execution of the downloaded file at every system startup:
- Registry:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
MicrosoftsSOftWare = %Program Data%\Microsofts Help\wsus.exe - Task Name: Microsoft System Protect
Schedule: At log on of user
Task to run: %Program Data%\Microsofts Help\wsus.exe
- Registry:
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)
It deletes the initially executed copy of itself
SOLUTION
9.850
14.826.06
20 Feb 2019
14.827.00
21 Feb 2019
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
Restart in Safe Mode
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
- MicrosoftsSOftWare = %Program Data%\Microsofts Help\wsus.exe
- MicrosoftsSOftWare = %Program Data%\Microsofts Help\wsus.exe
Step 5
Deleting Scheduled Tasks
The following {Task Name} - {Task to be run} listed should be used in the steps identified below:
- Task Name: Microsoft System Protect
- Task to run: %Program Data%\Microsofts Help\wsus.exe
For Windows 2000, Windows XP, and Windows Server 2003:
- Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
System Tools>Scheduled Tasks. - Locate each {Task Name} values listed above in the Name column.
- Right-click on the said file(s) with the aforementioned value.
- Click on Properties. In the Run field, check for the listed {Task to be run}.
- If the strings match the list above, delete the task.
For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:
- Open the Windows Task Scheduler. To do this:
• On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
• On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter. - In the left panel, click Task Scheduler Library.
- In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
- In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
- If the said string is found, delete the task.
Step 6
Disable this malware service
- foundation
Step 7
Search and delete these folders
- %ProgramData%\Microsofts Help
Step 8
Search and delete this file
- %ProgramData%\TMPUSER.dat
Step 9
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.WUSUB.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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