Worm.Win32.VOOLS.AO

 Analysis by: Carl Maverick Pascual

 ALIASES:

Trojan-CoinMiner (McAfee); Trojan.BitCoinMiner (MalwareBytes)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


This Worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It exploits software vulnerabilities to propagate to other computers across a network.

It deletes itself after execution. It uses the system's central processing unit (CPU) and/or graphical processing unit (GPU) resources to mine cryptocurrency.

  TECHNICAL DETAILS

File Size:

6,888,860 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Aug 2019

Payload:

Connects to URLs/IPs, Steals information, Drops files

Arrival Details

This Worm 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 Worm drops the following files:

  • %Windows%\NetworkDistribution\svchost.exe <- detected as TROJ_EQUATED.LZCMT
  • %Windows%\NetworkDistribution\spoolsv.exe <- detected as BKDR_EQUATED.LZCMU
  • %System%\dllhostex.exe <- detected as Coinminer.Win32.MALXMR.SMBM4
  • %System%\{Random Name}.dll <- detected as Trojan.Win32.VOOLS.SMAL01
    The name is generated by combining three (3) random strings from the following list:
    • Remote
    • Function
    • Secure
    • Microsoft
    • Network
    • Event
    • Manager
    • Service
    • Host
    • Client
    • NetBIOS
    • RPC
    • Protocol
    • Update
    • TimeUPnP
  • %System%\msvc{3-random character}.{random extension} <- contains encrypted shellcode
    The extension is randomly picked from the following list:
    • xsl
    • ini
    • dll
    • txt
    • log
    • dat
    • nls
  • Component files used for the malware's EternalBlue/DoublePulsar Exploitation:
    • %Windows%\NetworkDistribution\Diagnostics.txt
    • %Windows%\NetworkDistribution\Eternalblue-2.2.0.fb
    • %Windows%\NetworkDistribution\Eternalchampion-2.0.0.fb
    • %Windows%\NetworkDistribution\_pytrch.pyd
    • %Windows%\NetworkDistribution\adfw-2.dll
    • %Windows%\NetworkDistribution\adfw.dll
    • %Windows%\NetworkDistribution\cnli-0.dll
    • %Windows%\NetworkDistribution\cnli-1.dll
    • %Windows%\NetworkDistribution\coli-0.dll
    • %Windows%\NetworkDistribution\crli-0.dll
    • %Windows%\NetworkDistribution\dmgd-1.dll
    • %Windows%\NetworkDistribution\dmgd-4.dll
    • %Windows%\NetworkDistribution\esco-0.dll
    • %Windows%\NetworkDistribution\etch-0.dll
    • %Windows%\NetworkDistribution\etchCore-0.x64.dll
    • %Windows%\NetworkDistribution\etchCore-0.x86.dll
    • %Windows%\NetworkDistribution\eteb-2.dll
    • %Windows%\NetworkDistribution\etebCore-2.x64.dll
    • %Windows%\NetworkDistribution\etebCore-2.x86.dll
    • %Windows%\NetworkDistribution\exma-1.dll
    • %Windows%\NetworkDistribution\exma.dll
    • %Windows%\NetworkDistribution\iconv.dll
    • %Windows%\NetworkDistribution\libcurl.dll
    • %Windows%\NetworkDistribution\libeay32.dll
    • %Windows%\NetworkDistribution\libiconv-2.dll
    • %Windows%\NetworkDistribution\libxml2.dll
    • %Windows%\NetworkDistribution\out.dll
    • %Windows%\NetworkDistribution\pcla-0.dll
    • %Windows%\NetworkDistribution\pcre-0.dll
    • %Windows%\NetworkDistribution\pcrecpp-0.dll
    • %Windows%\NetworkDistribution\pcreposix-0.dll
    • %Windows%\NetworkDistribution\posh-0.dll
    • %Windows%\NetworkDistribution\posh.dll
    • %Windows%\NetworkDistribution\pytrch.py
    • %Windows%\NetworkDistribution\pytrch.pyc
    • %Windows%\NetworkDistribution\riar-2.dll
    • %Windows%\NetworkDistribution\riar.dll
    • %Windows%\NetworkDistribution\spoolsv.xml
    • %Windows%\NetworkDistribution\ssleay32.dll
    • %Windows%\NetworkDistribution\svchost.xml
    • %Windows%\NetworkDistribution\tibe-1.dll
    • %Windows%\NetworkDistribution\tibe-2.dll
    • %Windows%\NetworkDistribution\tibe.dll
    • %Windows%\NetworkDistribution\trch-0.dll
    • %Windows%\NetworkDistribution\trch-1.dll
    • %Windows%\NetworkDistribution\trch.dll
    • %Windows%\NetworkDistribution\trfo-0.dll
    • %Windows%\NetworkDistribution\trfo-2.dll
    • %Windows%\NetworkDistribution\trfo.dll
    • %Windows%\NetworkDistribution\tucl-1.dll
    • %Windows%\NetworkDistribution\tucl.dll
    • %Windows%\NetworkDistribution\ucl.dll
    • %Windows%\NetworkDistribution\x64.dll
    • %Windows%\NetworkDistribution\x86.dll
    • %Windows%\NetworkDistribution\xdvl-0.dll
    • %Windows%\NetworkDistribution\zibe.dll
    • %Windows%\NetworkDistribution\zlib1.dll

It adds the following processes:

  • sc stop RpcPolicyMgr
  • sc delete RpcPolicyMgr
  • %System%\schtasks.exe /End /tn "Microsoft\Windows\UPnP\RpcPolicyHost"
  • %System%\schtasks.exe /Delete /tn "Microsoft\Windows\UPnP\RpcPolicyHost"
  • cmd.exe /c ping 127.0.0.1 -n 5 & cmd.exe /c del /a /f {Malware File Name}
  • %System%\dllhostex.exe

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

It creates the following folders:

  • %Windows%\NetworkDistribution

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

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • {ED29R9-8ED1-C760-7D789N}
  • {CE9SCB-B92-FC8-A6FEDC}
  • {E2088B81F-2A96-43E8-B9F522B}
  • {F5175396-40C2-0218-278D6EE}
  • {B8A7AE22-7F59-CDE5-71F9C2A}

Autostart Technique

This Worm registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services
{DLL Name} = %System%\svchost.exe -k netsvcs

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Svchost
netsvcs = {Original Data} + {DLL Name}

(Note: The default value data of the said registry entry is {Original Data}.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{DLL Name}\Parameters
ServiceDLL = %System%\{Random DLL Name}

It starts the following services:

  • {Random DLL Name}

Other System Modifications

This Worm deletes the following files:

  • %Windows%\RemoteDistribution\spoolsv.exe
  • %Windows%\RemoteDistribution\Microsoft\spoolsv.exe
  • %Windows%\RemoteDistribution\Microsoft\svchost.exe
  • %System%\WUDHostServices.exe
  • %System%\ServicesMgrHost.exe
  • %System%\RpcPolicyMgr.dll
  • %System%\NdfPresentationView.msc
  • %System%\text.log

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

It deletes the following folders:

  • %Windows%\RemoteDistribution

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

It adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\NetworkPlatform\
Location Awareness
LastBackup = {Hex Values}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\NetworkPlatform\
Location
IPC = IPC

Propagation

This Worm exploits the following software vulnerabilities to propagate to other computers across a network:

Process Termination

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

  • %Windows%\RemoteDistribution\spoolsv.exe
  • %Windows%\RemoteDistribution\Microsoft\spoolsv.exe
  • %Windows%\RemoteDistribution\Microsoft\svchost.exe
  • %System%\WUDHostServices.exe
  • %System%\ServicesMgrHost.exe

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

Information Theft

This Worm gathers the following data:

  • Host Name
  • Local IP Address
  • MAC Address

Stolen Information

This Worm sends the gathered information via HTTP POST to the following URL:

  • log.{BLOCKED}.com:80/ipc.html?

Other Details

This Worm does the following:

  • It creates a random process from the following list:
    • svchost.exe
    • dllhost.exe
    • msdtc.exe
    • wuauclt.exe
    • wudfhost.exe
    • ctfmon.exe
    • searchfilterhost.exe
    • searchindexer.exe
    • searchprotocolhost.exe

    where it will inject its own malicious code for propagating local network via an SMB exploit (MS17-010)
  • Uses the following as the malicious coinminer configuration:
    z -o pool.boreye.com:53 -u IPC_eye1 -p x -t 1 --donate-level=1 -nicehash

It deletes itself after execution.

It uses the system's central processing unit (CPU) and/or graphical processing unit (GPU) resources to mine cryptocurrency. This behavior makes the system run abnormally slow.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.322.02

FIRST VSAPI PATTERN DATE:

26 Aug 2019

VSAPI OPR PATTERN File:

15.323.00

VSAPI OPR PATTERN Date:

27 Aug 2019

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, and then 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\CurrentControlSet\Services
    • {DLL Name}

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkPlatform\Location
    • LastBackup = {HEX Values}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkPlatform\Location
    • IPC = IPC

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Svchost
    • From: netsvcs = {Original Data} + {DLL Name}
      To: netsvcs = {Original Data}

Step 6

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%\msvc{3-random character}.{random extension}

Step 7

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Windows%\NetworkDistribution

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.VOOLS.AO. 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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