Analysis by: Cris Nowell Pantanilla
ALIASES:

Trojan.Win32.Trickster.dnq (Kaspersky)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

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: 6,263,906 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 22 Feb 2019

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 creates the following folders:

  • %User Temp%\_MEI{random digits}

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\_MEI{random digits}\_ctypes.pyd
  • %User Temp%\_MEI{random digits}\_hashlib.pyd
  • %User Temp%\_MEI{random digits}\_mssql.pyd
  • %User Temp%\_MEI{random digits}\_socket.pyd
  • %User Temp%\_MEI{random digits}\_ssl.pyd
  • %User Temp%\_MEI{random digits}\bz2.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Cipher._AES.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Cipher._ARC4.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Cipher._DES.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Cipher._DES3.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Hash._MD4.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Hash._SHA256.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Random.OSRNG.winrandom.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Util._counter.pyd
  • %User Temp%\_MEI{random digits}\Crypto.Util.strxor.pyd
  • %User Temp%\_MEI{random digits}\ii.exe.manifest
  • %User Temp%\_MEI{random digits}\Microsoft.VC90.CRT.manifest
  • %User Temp%\_MEI{random digits}\msvcm90.dll
  • %User Temp%\_MEI{random digits}\msvcp90.dll
  • %User Temp%\_MEI{random digits}\msvcr90.dll
  • %User Temp%\_MEI{random digits}\python27.dll
  • %User Temp%\_MEI{random digits}\pywintypes27.dll
  • %User Temp%\_MEI{random digits}\select.pyd
  • %User Temp%\_MEI{random digits}\unicodedata.pyd
  • %User Temp%\_MEI{random digits}\win32api.pyd
  • %User Temp%\_MEI{random digits}\win32pipe.pyd
  • %User Temp%\_MEI{random digits}\win32wnet.pyd
  • {malware path}\oskjwyh28s3.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.)

Other Details

This Trojan does the following:

  • It executes the following commands:
    • net user
    • netsh advfirewall set allprofile state on
    • netsh advfirewall firewall add rule name=denyy445 dir=in action=block protocol=TCP localport=445
    • netsh advfirewall firewall add rule name=denyy135 dir=in action=block protocol=TCP localport=135
    • netsh advfirewall firewall add rule name=denyy136 dir=in action=block protocol=TCP localport=136
    • netsh advfirewall firewall add rule name=denyy137 dir=in action=block protocol=TCP localport=137

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.834.06
FIRST VSAPI PATTERN DATE: 22 Feb 2019
VSAPI OPR PATTERN File: 14.835.00
VSAPI OPR PATTERN Date: 23 Feb 2019

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

Search and delete this folder

[ 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. %User Temp%\_MEI{random digits}

Step 3

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.  {malware path}\oskjwyh28s3.exe
%User Temp%\_MEI{random digits}\_ctypes.pyd
%User Temp%\_MEI{random digits}\_hashlib.pyd
%User Temp%\_MEI{random digits}\_mssql.pyd
%User Temp%\_MEI{random digits}\_socket.pyd
%User Temp%\_MEI{random digits}\_ssl.pyd
%User Temp%\_MEI{random digits}\bz2.pyd
%User Temp%\_MEI{random digits}\Crypto.Cipher._AES.pyd
%User Temp%\_MEI{random digits}\Crypto.Cipher._ARC4.pyd
%User Temp%\_MEI{random digits}\Crypto.Cipher._DES.pyd
%User Temp%\_MEI{random digits}\Crypto.Cipher._DES3.pyd
%User Temp%\_MEI{random digits}\Crypto.Hash._MD4.pyd
%User Temp%\_MEI{random digits}\Crypto.Hash._SHA256.pyd
%User Temp%\_MEI{random digits}\Crypto.Random.OSRNG.winrandom.pyd
%User Temp%\_MEI{random digits}\Crypto.Util._counter.pyd
%User Temp%\_MEI{random digits}\Crypto.Util.strxor.pyd
%User Temp%\_MEI{random digits}\ii.exe.manifest
%User Temp%\_MEI{random digits}\Microsoft.VC90.CRT.manifest
%User Temp%\_MEI{random digits}\msvcm90.dll
%User Temp%\_MEI{random digits}\msvcp90.dll
%User Temp%\_MEI{random digits}\msvcr90.dll
%User Temp%\_MEI{random digits}\python27.dll
%User Temp%\_MEI{random digits}\pywintypes27.dll
%User Temp%\_MEI{random digits}\select.pyd
%User Temp%\_MEI{random digits}\unicodedata.pyd
%User Temp%\_MEI{random digits}\win32api.pyd
%User Temp%\_MEI{random digits}\win32pipe.pyd
%User Temp%\_MEI{random digits}\win32wnet.pyd

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.ZPEVDO.AE. 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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