arrow_back
search
close

BKDR_NEUREVT.LML

August 17, 2015
 ALIASES:

Trojan:Win32/Neurevt.AB (Microsoft), Trojan.Win32.Neurevt.dvb (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It executes commands from a remote malicious user, effectively compromising the affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

237,568 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

05 Jun 2015

Payload:

Compromises system security, Connects to URLs/IPs

Arrival Details

This backdoor 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 backdoor drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\AudioDriverSFX\ftwxlmwgs.exe

(Note: %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 injects codes into the following process(es):

  • wuauclt.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Windows Update Service = "%Program Files%\Common Files\AudioDriverSFX\ftwxlmwgs.exe"

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
TaskbarNoNotification = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
BavUpdater.exe
Debugger = "{ransom string}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
adaware.exe
Debugger = "{ransom string}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
niu.exe
Debugger = "{ransom string}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
guardxup.exe
Debugger = "{ransom string}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
mbamgui.exe
Debugger = "{ransom string}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
mbam.exe
Debugger = "{ransom string}.exe"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download files
  • Upload files
  • Copy itself in removable drives
  • Start or stop programs
  • Delete files

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • update.microsoft.com
  • microsoft.com
  • windowsupdate.microsoft.com

It deletes the initially executed copy of itself

NOTES:

It queries the following registry key to get the processor information:

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor

It queries the following registry key to get Microsoft Net Framework Version:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Net Framework setup\NDP

It scans the system for the following Antivirus and Security Related processes then terminates them:

  • Symantec
  • AVG
  • Kaspersky
  • avast! Antivirus
  • Microsoft Security Essentials
  • Bdagent
  • Trend Micro Titanium
  • McAfee
  • Sophos
  • ArcaBit
  • Baidu Antivirus
  • Webroot SecureAnywhere
  • ZoneAlarm
  • F-Secure
  • Panda
  • Bkav
  • Ad-Aware
  • BullGuard
  • Rising Antivirus
  • PC Tools Protection
  • VIPRE Antivirus
  • F-PROT
  • Outpost Security Suite
  • Norman Data Defense Systems
  • K7
  • Ikarus
  • CA Anti-Virus
  • Emsisoft Anti-Malware
  • Comodo Antivirus
  • G Data AntiVirus
  • AhnLab V3
  • Malwarebytes

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.710.09

FIRST VSAPI PATTERN DATE:

05 Jun 2015

VSAPI OPR PATTERN File:

11.711.00

VSAPI OPR PATTERN Date:

05 Jun 2015

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Windows Update Service = "%Program Files%\Common Files\AudioDriverSFX\ftwxlmwgs.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • TaskbarNoNotification = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\BavUpdater.exe
    • Debugger = "{ransom string}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\adaware.exe
    • Debugger = "{ransom string}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\niu.exe
    • Debugger = "{ransom string}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\guardxup.exe
    • Debugger = "{ransom string}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\mbamgui.exe
    • Debugger = "{ransom string}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\mbam.exe
    • Debugger = "{ransom string}.exe"

Step 4

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


Did this description help? Tell us how we did.