Analysis by: Jeanne Jocson
ALIASES:

Trojan.Win32.KillDisk.fx (Kaspersky), Win32/KillDisk.NBK trojan (NOD32), Trojan.Disakil (Symantec)

 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: 204,800 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Dec 2016
Payload: Terminates processes, Restarts system, Encrypts files,

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\updcent
DisplayName = System update center

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

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

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\updcent
Start= = "2"

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\updcent\Enum
0 = "Root\LEGACY_UPDCENT\0000"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\updcent\Enum
Count = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\updcent\Enum
NextInstance = "1"

It adds and runs the following services:

  • updcent (System update center)

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\updcent

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
UpdateCenter

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
UpdateCenter
LastUpdate = {value}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
UpdateCenter
FirstUpdate = {value}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
UpdateCenter
NextUpdate = {value}

Other Details

This Trojan encrypts files with the following extensions:

  • .3ds
  • .7z
  • .accdb
  • .accdc
  • .ai
  • .asp
  • .aspx
  • .avhd
  • .back
  • .bak
  • .bin
  • .bkf
  • .cer
  • .cfg
  • .conf
  • .crl
  • .crt
  • .csr
  • .csv
  • .dat
  • .db3
  • .db4
  • .dbc
  • .dbf
  • .dbx
  • .djvu
  • .doc
  • .docx
  • .dr
  • .dwg
  • .dxf
  • .edb
  • .eml
  • .fdb
  • .gdb
  • .git
  • .gz
  • .hdd
  • .ib
  • .ibz
  • .io
  • .jar
  • .jpeg
  • .jpg
  • .jrs
  • .js
  • .kdbx
  • .key
  • .mail
  • .max
  • .mdb
  • .mdbx
  • .mdf
  • .mkv
  • .mlk
  • .mp3
  • .msi
  • .my
  • .myd
  • .nsn
  • .oda
  • .ost
  • .ovf
  • .p7b
  • .p7c
  • .p7r
  • .pd
  • .pdf
  • .pem
  • .pfx
  • .php
  • .pio
  • .piz
  • .png
  • .ppt
  • .pptx
  • .ps
  • .ps1
  • .pst
  • .pvi
  • .pvk
  • .py
  • .pyc
  • .rar
  • .rb
  • .rtf
  • .sdb
  • .sdf
  • .sh
  • .sl3
  • .spc
  • .sql
  • .sqlite
  • .sqlite3
  • .tar
  • .tiff
  • .vbk
  • .vbm
  • .vbox
  • .vcb
  • .vdi
  • .vfd
  • .vhd
  • .vhdx
  • .vmc
  • .vmdk
  • .vmem
  • .vmfx
  • .vmsd
  • .vmx
  • .vmxf
  • .vsd
  • .vsdx
  • .vsv
  • .wav
  • .wdb
  • .xls
  • .xlsx
  • .xvd
  • .zip

It does the following:

  • It accepts the following arguments:
    • -set={value} → used to set time
    • -est={value}
    • -opt={param}
      where {param} can be any of the following:
      • frc → encrypt files
      • chk
      • cnc
      • pic → display image
      • svc → run as service
  • 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
  • Reboot the system

NOTES:

It may display the following image:

  SOLUTION

Minimum Scan Engine: 9.800

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 ]
    • updcent(System update center)

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\SYSTEM\CurrentControlSet\Services
    • updcent
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • UpdateCenter

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_KILLDISK.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 this Knowledge Base page for more information.

Step 7

Scan your computer with your Trend Micro product to delete files detected as RANSOM_KILLDISK.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 this Knowledge Base page for more information.

Step 8

Restore encrypted files from backup.


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