Analysis by: Bren Matthew Ebriega
ALIASES:

Trojan.Win32.Tasker.zm (KASPERSKY)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Potentially Unwanted Application 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

File Size: 77,824 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 13 Nov 2020
Payload: Drops files, Terminates processes

Arrival Details

This Potentially Unwanted Application 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 Potentially Unwanted Application drops the following files:

  • %System Root%\McAfeeWMIMonitor.txt → Contains activity logs.

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It drops the following copies of itself into the affected system:

  • %System Root%\McAfeeWMIMonitor2_0.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It adds the following processes:

  • %System%\schtasks.exe /create /F /ru "SYSTEM" /SC ONSTART /TN "McAfeeWMIMonitor2_0" /TR "\"%System Root%\McAfeeWMIMonitor2_0.exe\"\"/stdate:{Date Started}\""
  • %System Root%\McAfeeWMIMonitor2_0.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Process Termination

This Potentially Unwanted Application terminates the following processes if found running in the affected system's memory:

  • taskservice.exe
  • cmd.exe
  • powershell.exe
  • wscript.exe
  • If they contain any of the following strings in their commandline:
    • *MSXLM2.XMLHTTP*
    • *Office_Updated*
    • *Win32_TaskService*
    • *DownloadString*
    • *in*.ps*
    • *ma*.ps*
    • *in*.vbs
    • *stratum+tcp*
    • *@($mon*
    • *JAB*

Other Details

This Potentially Unwanted Application does the following:

  • It will delete and remove itself after thirty(30) days.
  • It deletes WMI objects that match the following criteria:
    • If its Executable Path contains any of the following strings:
      • cscript
      • wscript
    • If its CommandLineTemplate contains any of the following strings:
      • powershell -nop -noni -w hidden
      • stratum+tcp://
      • tcpconn = netstat -anop tcp
    • If it has the following Properties:
      • mimi
      • mon
      • funs
      • Mine
    • If its Property contents contain any of the following strings:
      • security_blob_bytes
      • ntlmv2_response_length
      • packet_rpc
      • function invoke-createremotethread
      • this program cannot be run in dos mode

It adds the following scheduled tasks:

  • Task Name: McAfeeWMIMonitor2_0
    Trigger: At System Startup
    Task Action: %System Root%\McAfeeWMIMonitor2_0.exe "/stdate:{Date Started}"

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

  SOLUTION

Minimum Scan Engine: 9.800
SSAPI PATTERN File: 2.415.00
SSAPI PATTERN Date: 10 Jun 2021

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.XXPE50FFF045

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

[ Learn More ]

Step 5

Identify and terminate files detected as PUA.MSIL.ProcmiMonitor.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 6

Deleting Scheduled Tasks

The following {Task Name} - {Task to be run} listed should be used in the steps identified below:

  • Task Name: McAfeeWMIMonitor2_0
    Task to be run: %System Root%\McAfeeWMIMonitor2_0.exe /stdate:{Date Started}

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. Click Start>Programs>Accessories>
    System Tools>Scheduled Tasks.
  2. Locate each {Task Name} values listed above in the Name column.
  3. Right-click on the said file(s) with the aforementioned value.
  4. Click on Properties. In the Run field, check for the listed {Task to be run}.
  5. 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:

  1. 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.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each {Task Name} values listed above in the Name column.
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the {Task to be run} string.
  5. If the said string is found, delete the task.

Step 7

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %System Root%\McAfeeWMIMonitor.txt

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PUA.MSIL.ProcmiMonitor.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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