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WORM_DISTTRACK.C

January 23, 2017
 Analysis by: RonJay Kristoffer Caragay
 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: Yes

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via network shares, 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 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:

1,349,632 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

19 Nov 2016

Payload:

Corrupts hard disk, Deletes 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 copies of itself into the affected system and executes them:

  • %System%\ntssrvr32.exe

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

It 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%\netinit.exe ← detected as TROJ_DISTTRACK.C; used to Report Infection
  • %System%\{random filename}.exe ← detected as TROJ_WIPMBR.C; used to wipe MBR
      where {random filename} is any of the following:
    • caclsrv
    • certutl
    • clean
    • ctrl
    • dfrag
    • dnslookup
    • dvdquery
    • event
    • findfile
    • gpget
    • ipsecure
    • iissrv
    • msinit
    • ntfrsutil
    • ntdsutl
    • power
    • rdsadmin
    • regsys
    • sigver
    • routeman
    • rrasrv
    • sacses
    • sfmsc
    • smbinit
    • wcscript
    • ntnw
    • netx
    • fsutl
    • extract

(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:

  • ADMIN$
  • C$\WINDOWS
  • D$\WINDOWS
  • 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\NtsSrv
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtsSrv
ImagePath = "%System%\ntssrvr32.exe LocalService" or "{malware path and filename} LocalService"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtsSrv
DisplayName = "Microsoft Network Realtime Inspection Service"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtsSrv
DependOnService = "RpcSs"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtsSrv
DependOnGroup = "0"

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\NtsSrv
Description = "Helps guard against time change attempts targeting known and newly discovered vulnerabilities in network time protocols"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\LanmanWorkstation
DependOnGroup = ""

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\LanmanWorkstation
DependOnService = NtsSrv

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.906.08

FIRST VSAPI PATTERN DATE:

18 Nov 2016

VSAPI OPR PATTERN File:

12.907.00

VSAPI OPR PATTERN Date:

19 Nov 2016

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
  • TROJ.WIN32.TRX.XXPE0007

Step 2

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

Remove the malware/grayware file dropped/downloaded by WORM_DISTTRACK.C. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • TROJ_DISTTRACK.C
    • TROJ_WIPMBR.C

Step 6

Delete this registry key

[ 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\SYSTEM\CurrentControlSet\Services
    • NtsSrv

Step 7

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.
  • %Temp%\key8854321.pub

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_DISTTRACK.C. 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 9

Delete these 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\SYSTEM\CurrentControlSet\Services\LanmanWorkstation
    • DependOnGroup = ""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation
    • DependOnService = NtsSrv


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