TROJ_NEUREVT.TAG

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

Troj/Mdrop-GSU (Sophos); Trojan:Win32/Dynamer!ac (Microsoft); Trojan-Ransom.NSIS.Onion.xv (Kaspersky); Nsis.Trojan.Onion.Htvp (Tencent); Trojan.NSIS.Ransom.xv (Baidu-International)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

405,423 bytes

File Type:

EXE

Initial Samples Received Date:

22 Jun 2015

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 drops the following copies of itself into the affected system and executes them:

  • %ProgramData%\MS Word 2015\{random filename}.exe (for Windows Vista and above)
  • %Program Files%\Common Files\MS Word 2015\{random filename}.exe (for Windows XP and below)

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops the following files:

  • %Application Data%\NLEastPreview_0k987akk_d31fpjh9.jpg
  • %Application Data%\08 - Bloc Party - Kreuzberg.mp3
  • %Application Data%\78auidawui1awdunawdk
  • %User Temp%\nsw1C.tmp\Evesham.dll
  • %User Temp%\mdcVBuh5anGQpbs-wtB9AD0JTFmzKdb-kalumD9c0H1WwYB-rMeiXDVgucN8HOw.exe

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It creates the following folders:

  • %ProgramData%\MS Word 2015 (for Windows Vista and above)
  • %Program Files%\Common Files\MS Word 2015 (for Windows XP and below)

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
MS Word 2015 = "%Program Files%\Common Files\MS Word 2015\{random filename}.exe" (for Windows XP and below)

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
MS Word 2015 = "%Program Files%\Common Files\MS Word 2015\{random filename}.exe" (for Windows XP and below)

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
MS Word 2015 = "%ProgramData%\MS Word 2015\{random filename}.exe" (for Windows Vista and above)

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunOnce
MS Word 2015 = "%ProgramData%\MS Word 2015\{random filename}.exe" (for Windows Vista and above)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\08 - Bloc Party - Kreuzberg.mp3

HKEY_CURRENT_USER\Software\AppDataLow\
Software\{UID}

HKEY_CURRENT_USER\Software\AppDataLow\
Software\MyMailClient

HKEY_CURRENT_USER\Software\AppDataLow\
Google Updater (for Windows Vista and above)

HKEY_CURRENT_USER\Software\Logitech, Inc. (for Windows XP and below)

It adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
{random filename}.exe
DisableExceptionChainValidation = ""

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\1
2500 = "3"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\2
2500 = "3"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
2500 = "3"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\4
2500 = "3"

HKEY_CURRENT_USER\Software\AppDataLow\
Google Updater
LastUpdate = "{hex values}" (for Windows Vista and above)

HKEY_CURRENT_USER\Software\Logitech, Inc.
WindowLayout = "{hex values}" (for Windows XP and below)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}omnabouna.org/img/logout.php
  • http://{BLOCKED}mnabouna.com/img/logout.php
  • http://{BLOCKED}omnabouna.net/img/logout.php

It deletes itself after execution.