Analysis by: David John Agni
ALIASES:

Trojan:Win64/Depriz.D!dha (Microsoft), Win64/DistTrack.C (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via network shares, Downloaded from the Internet, Dropped by other malware

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 uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 133,2224 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 Jan 2017
Payload: Drops files

Arrival Details

This worm may arrive via network shares.

It 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 component file(s):

  • %Temp%\key8854321.pub ← contains Public Key

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

It drops and executes the following files:

  • %System%\{comms name} - detected as TROJ64_DISTTRACK.D used to report infection.
  • %System%\{wiper name} - detected as TROJ64_WIPMBR.D used to wipe MBR

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

It drops the following copies of itself into the affected system:

  • %System%\ntertmgr32.exe - 32 bit system
  • %System%\ntertmgr64.exe - 64 bit system

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

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

Propagation

This worm drops copies of itself in the following shared folders:

  • \{Computer Name}\ADMIN$
  • \{Computer Name}\C$\WINDOWS
  • \{Computer Name}\D$\WINDOWS
  • \{Computer Name}\E$\WINDOWS

Dropping Routine

This worm executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

This worm adds and runs the following services:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
DependOnService = "RpcSs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
DisplayName = "Extensible Remote Tab"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\NtertSrv
Description = "The Extensible Remote Tab manager service determines the index of current Tab in the general Tab system, Also provides application programming interfaces (APIs) that are used by some other applications. If you disable this service, this computer is prevented from \system32\csrss.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtertSrv
ImagePath = "{drop copy} LocalService" or "{malware path and filename} LocalService"

NOTES:

Where {comms name} is any of the following:

  • caiaw00e.exe
  • sbuvideo.exe
  • caiaw00i.exe
  • olvume.exe
  • usinwb2.exe
  • briaw005.exe
  • fpwwlwf.exe
  • epiaw003.exe
  • briaw002.exe
  • olvsnap.exe
  • dmwaudio.exe
  • briaw006.exe
  • miWApRpl.exe
  • caiaw00b.exe
  • lxiaw003.exe

Where {wiper name} is any of the following:

  • pdwmtphw.exe
  • caiaw00a.exe
  • sdwprint.exe
  • caiaw00d.exe
  • kyiaw002.exe
  • sdwscdrv.exe
  • briaw00a.exe
  • saiaw002.exe
  • _mvscdsc.exe
  • hdvmp32.exe
  • _s3wcap32.exe
  • hpiaw001.exe
  • lxiaw004.exe
  • cniaw001.exe
  • lxiaw006.exe
  • caiaw00f.exe
  • newtvsc.exe

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 13.150.08
FIRST VSAPI PATTERN DATE: 08 Jan 2017
VSAPI OPR PATTERN File: 13.151.00
VSAPI OPR PATTERN Date: 09 Jan 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

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

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
    • NtertSrv

Step 5

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.
  • %Temp%\key8854321.pub

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM64_DISTTRACK.D. 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

Remove malware/grayware files that dropped/downloaded WORM64_DISTTRACK.D. (Note: Please skip this step if the threats listed below have already been removed.)

    • TROJ64_DISTTRACK.D
    • TROJ64_WIPMBR.D


Did this description help? Tell us how we did.