TrojanSpy.MSIL.TRICKBOT.YXAK-A
Windows
Threat Type: Trojan Spy
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It executes then deletes itself afterward.
TECHNICAL DETAILS
Arrival Details
This Trojan Spy 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 Spy drops the following files:
- %Public%\stsk.exe -> Copy of legitimate schtasks.exe, deleted after creating the scheduled task
(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)
It drops the following copies of itself into the affected system:
- %Public%\winlogon.exe -> Only if the executable path is not equal to %Public%\winlogon.exe
(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)
It adds the following processes:
- %System%\cmd.exe /C choice /C Y /N /D Y /T 10 & "%Public%\winlogon.exe" -> Only if the executable path is not equal to %Public%\winlogon.exe
- %System%\cmd.exe /C choice /C Y /N /D Y /T 5 & Del "{Malware Path}\{Malware Filename}.exe" & Del %Public%\tmp.bat & Del %Public%\tmpdir\tmpd.bat & Del %Public%\tmpdir\tmps.bat & rd %Public%\tmpdir -> Only if the executable path is not equal to %Public%\winlogon.exe
- %Public%\stsk.exe /create /tn "Task5H3DKU8" /tr %Public%\winlogon.exe /sc onlogon
- %System%\cmd.exe /C choice /C Y /N /D Y /T 10 & Del "%Public%\winlogon.exe" -> Only if the computer name is WALKER-PC
(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)
It executes then deletes itself afterward.
Other System Modifications
This Trojan Spy deletes the following files:
- %Public%\studio.exe -> if found existing
(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)
Information Theft
This Trojan Spy gathers the following data:
- Computer Name
- IP Address
- MAC Address
Other Details
This Trojan Spy connects to the following possibly malicious URL:
- https://{BLOCKED}alysis.live/WebPanel/db_proc.php/?func=add_comp&name={Computer name}-{Mac Address}-QQQ
- https://{BLOCKED}alysis.live/WebPanel/db_proc.php/?func=still_alive&name={Computer name}-{Mac Address}-QQQ
It does the following:
- If it is not running on the following virtual environments:
- KVM
- VirtualBox
- vmware
- It would check if 'KMS Server Service' is running, if not it would access the following url to download a file:
- http://{BLOCKED}.{BLOCKED}.56.223/tLv6kz -> saves the file it downloads as %Public%\studio.exe
It adds the following scheduled tasks:
- Task Name: Task5H3DKU8
- Trigger: At user log on
- Action: Start a program: %Public%\winlogon.exe
(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)
SOLUTION
Step 1
Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:
- Troj.Win32.TRX.XXPE50FFF038
Step 2
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 3
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 4
Restart in Safe Mode
Step 5
Deleting Scheduled Tasks
The following {Task Name} - {Task to be run} listed should be used in the steps identified below:
- Task5H3DKU8 - %Public%\winlogon.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
Search and delete this file
- %Public%\winlogon.exe
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TrojanSpy.MSIL.TRICKBOT.YXAK-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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