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TrojanSpy.Win32.ZENPAK.A

August 12, 2019
 Analysis by: Henry Alarcon Jr.
 ALIASES:

Trojan.SpyBot.849 (DrWeb), Trojan.Win32.Zenpak.fsv (Kaspersky), Trojan:Win32/Wacatac.B!ml (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This Trojan Spy may be dropped by other malware.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

242,877 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 Aug 2019

Payload:

Connects to URLs/IPs

Arrival Details

This Trojan Spy may be dropped by the following malware:

Installation

This Trojan Spy drops the following files:

  • %All Users Profile%\0 ← marker if run as admin or not

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It drops and executes the following files:

  • %All Users Profile%\216c40503e\kndt.exe

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

It creates the following folders:

  • %All Users Profile%\216c40503e

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

Other System Modifications

This Trojan Spy modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Startup = %All Users Profile%\216c40503e

(Note: The default value data of the said registry entry is %USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup.)

Other Details

This Trojan Spy connects to the following website to send and receive information:

  • http://{BLOCKED}ns.com/ppk/index.php
  • http://{BLOCKED}u.top/ppk/index.php
  • http://{BLOCKED}e.net/ppk/index.php

    Here are the details of the message sent to C&C:
    • id - Volume Serial Number
    • sd - 363333
    • vs - 1.41
    • ar - 1 if executed as admin else 0
    • bi - OS Architecture
      • 1 = x86
      • 0 = x64
    • lv - running malware
      • 0 = 1.exe
      • 1 = kndt.exe
    • os - OS version, value can be the following:
      • 1 or 2 = Windows 10, Windows 8,Windows Server 2016, Windows Server 2012
      • 3 or 4 = Windows 8.1, Windows Server 2012 R2
      • 7 or 8 = Windows Vista, Windows Server 2008
      • 9 or 10 = Windows 7, Windows Server 2008 R2
      • 11 = SM_TABLETPC {system configuration setting}
      • 12 or 13 = Windows Server 2003 R2, Windows Home Server, Windows Server 2003
      • 14 = Windows XP
      • 15 = Windows 2000
    • av - value can be [1-12], folder exist %All Users Profile%\{AV}
      where "AV" folder name are the following:
      • 1 = AVAST Software
      • 2 = Avira
      • 3 = Kaspersky Lab
      • 4 = ESET
      • 5 = Panda Security
      • 6 = Doctor Web
      • 7 = AVG
      • 8 = 360TotalSecurity
      • 9 = Bitdefender
      • 10 = Norton
      • 11 = Sophos
      • 12 = Comodo
    • pc - Computer Name
    • un - UserName

It does the following:

  • It won't drop and execute if the following folders is found on the system:
    • %All Users Profile%\Norton
    • %All Users Profile%\Sophos
  • It create a registry modification if the following folder found in the system:
    • %All Users Profile%\360TotalSecurity

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.282.05

FIRST VSAPI PATTERN DATE:

06 Aug 2019

VSAPI OPR PATTERN File:

15.283.00

VSAPI OPR PATTERN Date:

07 Aug 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Identify and terminate files detected as TrojanSpy.Win32.ZENPAK.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Restore this modified registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
    • From: Startup = "%All Users Profile%\216c40503e"
      To: Startup = "%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup"

Step 5

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %All Users Profile%\216c40503e

Step 6

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.
  • %All Users Profile%\0

Step 7

Scan your computer with your Trend Micro product to delete files detected as TrojanSpy.Win32.ZENPAK.A. 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 the following Trend Micro Support pages for more information:


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