Analysis by: RonJay Kristoffer Caragay
ALIASES:

Trojan:Win32/KillDisk.N!dha (Microsoft); Trojan.Win32.KillDisk.fv (Kaspersky); W32/KillDisk.NBI!tr (Fortinet); Trojan.Win32.KillDisk (Ikarus); a variant of Win32/KillDisk.NBI (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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: 167,936 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 16 Dec 2016
Payload: Terminates processes, Restarts system

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 terminates itself if it finds the following processes in the affected system's memory:

  • avp.exe
  • avpui.exe
  • ekrn.exe
  • egui.exe
  • mfemmc.exe
  • mfefire.exe
  • mfevtps.exe
  • pefservice.exe
  • mcsvhost.exe
  • msascui.exe
  • msmpeng.exe
  • mpcmdrun.exe

Autostart Technique

This Trojan 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\pnpsup
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup
Type = "10"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup
ImagePath = "{malware path and filename} -opt=svc"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup
DisplayName = "Plug-And-Play Support"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup\Enum
0 = "Root\LEGACY_PNPSUP\0000"

It adds and runs the following services:

  • pnpsup (Plug-And-Play Support)

It registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\pnpsup

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Help

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Help\Core

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Help\Core
Support = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Help\Core
Validate = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Help\Core
Update = "1"

Other Details

This Trojan drops the following file(s)/component(s):

  • __{random numbers}__

It does the following:

  • It deletes shadow copies by executing the following command:
    • vssadmin delete shadows /all /quiet
  • It accepts the following arguments:
    • -set={value} → used to set time
    • -est={value}
    • -opt={param}
      where {param} can be any of the following:
      • frc → corrupt system
      • chk
      • cnc
      • pic → display image
      • svc → run as service
  • It clears the Windows Event Logs using wevutil.exe with the following parameters:
    • wevutil clear-log Application
    • wevutil clear-log Security
    • wevutil clear-log Setup
    • wevutil clear-log System
  • It may terminate any process except the following:
    • smss.exe
    • csrss.exe
    • wininit.exe
    • services.exe
    • lsass.exe
    • lsm.exe
    • svchost.exe
    • winlogon.exe
    • explorer.exe
    • dwm.exe
    • wuauclt.exe
    • spoolss.exe
    • spoolsv.exe
    • audiodg.exe
    • taskhost.exe
    • conhost.exe
    • shutdown.exe
  • Wipe Master Boot Record (MBR)
  • Modify Account Control using the following commands:
    • %System%\cacls.exe {drivepath} /T /C /G {username}:F
    • %System%\icacls.exe {drivepath} /T /C /Q /grant {username}:(F)
  • Destroy affected system by corrupting system files
  • Reboot the system

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

NOTES:

This Trojan may display the following image:

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 13.106.05
FIRST VSAPI PATTERN DATE: 20 Dec 2016
VSAPI OPR PATTERN File: 13.107.00
VSAPI OPR PATTERN Date: 21 Dec 2016

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

Disable this malware service

[ Learn More ]
    • pnpsup (Plug-And-Play Support)

Step 5

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\SOFTWARE\Microsoft
    • Help
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • pnpsup

Step 6

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.
  • __{random numbers}__

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_KILLDISK.ITX. 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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