BKDR_BANDOK.FQ

 Analysis by: Rheniel Rhay Ramos

 ALIASES:

Trojan-Spy.Win32.Zbot.yfeu (Kaspersky), Backdoor:Win32/Remteamvi (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • 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 retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

570,528 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

28 May 2017

Payload:

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

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%\arl\arl.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.)

It drops the following files:

  • %Application Data%\mw.html -> (deleted afterwards)

(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.)

It adds the following processes:

  • iexplore.exe

It creates the following folders:

  • %Application Data%\arl

(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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Ddsdiewewdid
  • 4dfewewfdfdf
  • Kod333
  • Ksdksdewewksdks9
  • FKffkewdf

It injects codes into the following process(es):

  • iexplore.exe (added process)

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
arl = "%Application Data%\arl\arl.exe"

Other System Modifications

This Backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software\arl
rno1 = "{Random Numbers}.exe"

HKEY_CURRENT_USER\Software\arl
gn = "{Random Numbers}.exe"

HKEY_CURRENT_USER\Software\arl
mep = "{Random Numbers}"

HKEY_CURRENT_USER\Software\arl
api = "{Random Numbers}"

HKEY_CURRENT_USER\Software\arl
pim = "{Random Numbers}"

HKEY_CURRENT_USER\Software\arl
tvn = "{Random Numbers}.exe"

HKEY_CURRENT_USER\Software
jDHc = "{Random Numbers}"

Backdoor Routine

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

  • AddAutoFTPToDB
  • CaptureScreen
  • ChromeInject
  • ClearCred
  • CompressArchive
  • CopyMTP
  • DeleteAutoFTPFromDB
  • DeleteFileFromDevice
  • DisableChrome
  • DisableMouseCapture
  • EnableAndLoadCapList
  • GenerateReports
  • GetAutoFTP
  • GetCamlist
  • GetFileMONLIST
  • GetSound
  • GetUSBMONLIST
  • GetWifi
  • GrabFileFromDevice
  • PutFileOnDevice
  • RarFolder
  • SearchMain
  • SendCam
  • SendFileMonLog
  • SendMTPList
  • SendMTPList2
  • SendStartup
  • SendUSBList
  • SendinfoList
  • SignoutSkype
  • SplitMyFile
  • StartFileMonitor
  • StartShell
  • StealUSB
  • StopCam
  • StopFileMonitor
  • StopSearch
  • StopUSBMonitor
  • Uninstall
  • getkey

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

  • {BLOCKED}x.net
  • http://{BLOCKED}x.net/dxb2/

Download Routine

This Backdoor connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}x.net/plg10/

It saves the files it downloads using the following names:

  • %Application Data%\arl\cpm.dll
  • %Application Data%\arl\pmd.dll
  • %Application Data%\arl\22289.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.)

Information Theft

This Backdoor retrieves the following information from the affected system:

  • User Name
  • Computer Name
  • OS Version
  • IP Address

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

13.942.05

FIRST VSAPI PATTERN DATE:

19 Jan 2018

VSAPI OPR PATTERN File:

13.943.00

VSAPI OPR PATTERN Date:

20 Jan 2018

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 key

[ 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
    • arl

Step 4

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
    • arl = "%Application Data%\arl\arl.exe"
  • In HKEY_CURRENT_USER\Software
    • jDHc = "{Random Numbers}"

Step 5

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.
  • %Application Data%\arl

Step 6

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