BKDR_ANDROM.NJS

August 20, 2018
 Analysis by: Jaime Benigno Reyes
 Modified by: Augusto II Remillano
 ALIASES:

Backdoor.Win32.Androm.fnox (Kaspersky), Backdoor.Androm (VBA32)

 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 connects to a website to send and receive information.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

90,624 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Aug 2018

Payload:

Compromises system security, Connects to URLs/IPs, Steals information

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 and executes them:

  • %Application Data%\ms{random}.exe
  • %ProgramData%\ms{random}.exe (if run as Administrator)

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.)

It adds the following processes:

  • msiexec.exe

It injects codes into the following process(es):

  • msiexec.exe
  • explorer.exe

It terminates itself if it finds the following processes in the affected system's memory:

  • vmwareuser.exe
  • vmwareservice.exe
  • vboxservice.exe
  • vboxtray.exe
  • sandboxiedcomlaunch.exe
  • sandboxierpcss.exe
  • procmon.exe
  • regmon.exe
  • filemon.exe
  • wireshark.exe
  • netmon.exe
  • prl_tools_service.exe
  • prl_tools.exe
  • prl_cc.exe
  • sharedintapp.exe
  • vmtoolsd.exe
  • Vmsrvc.exe
  • vmusrvc.exe

Autostart Technique

This Backdoor modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random number} = "%Application Data%\ms{random}.exe" or "%ProgramData%\ms{random}.exe" if run as Administrator

Other System Modifications

This Backdoor modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
TaskbarNoNotification = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
HideSCAHealth = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

Backdoor Routine

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

  • Download exe
  • Update plug-in
  • Delete bot
  • Install plug-in

It connects to the following websites to send and receive information:

  • http://{BLOCKED}ashkd1.ru/and/gate.php

It posts the following information to its command and control (C&C) server:

  • OS version
  • VolumeSerialNumber
  • Local IP address
  • Botnet ID
  • Administrator rights of current malware process

As of this writing, the said sites are inaccessible.

Process Termination

This Backdoor terminates the following services if found on the affected system:

  • wscsvc
  • SharedAccess
  • MpsSvc
  • WinDefend
  • wuauserv

Other Details

This Backdoor deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

11.312.04

FIRST VSAPI PATTERN DATE:

01 Dec 2014

VSAPI OPR PATTERN File:

11.313.00

VSAPI OPR PATTERN Date:

02 Dec 2014

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

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

Restart in Safe Mode

[ Learn More ]

Step 4

Restore this modified 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\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MpsSvc
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinDefend
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wscsvc
    • From: Start = "4"
      To: Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wuauserv
    • From: Start = "4"
      To: Start = "2"

Step 5

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
    • {random number} = "%Application Data%\ms{random}.exe"

Step 6

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


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