BKDR_MOKES.A

 Analysis by: David John Agni

 ALIASES:

Backdoor.Win32.Mokes.imw (Kaspersky)

 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:

Downloaded from the Internet, Dropped by other malware


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 runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

  TECHNICAL DETAILS

File Size:

4,095,008 bytes

File Compression:

UPX

Memory Resident:

Yes

Initial Samples Received Date:

02 Feb 2016

Payload:

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 and executes the following files:

  • File may be dropped in any of the following locations:
    %AppData%\Skype\SkypeHelper.exe
    %AppData%\Dropbox\bin\DropboxHelper.exe
    %AppData%\Google\Chrome\nacl32.exe
    %AppData%\Google\Chrome\nacl64.exe
    %AppData%\Mozilla\Firefox\mozillacache.exe
    %AppData%\Hewlett-Packard\hpqcore.exe
    %AppData%\Hewlett-Packard\hpprint.exe
    %AppData%\Hewlett-Packard\hpscan.exe
    %AppData%\Adobe\Acrobat\AcroBroker.exe

It drops the following non-malicious files:

  • {malware dropped copy folder}\version - contains malware version and full path of the dropped copy

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
{malware dropped copy filename} = "{full path of the dropped copy}"

Backdoor Routine

This backdoor executes the following command(s) from a remote malicious user:

  • Keylogging and monitors mouse inputs
  • Capture screenshots
  • Capture audio
  • Capture images from installed camera

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}.{BLOCKED}.216.165/v1
  • http://{BLOCKED}.{BLOCKED}.216.165:2311/v1
  • http://{BLOCKED}.{BLOCKED}.97.234/v1
  • http://{BLOCKED}ates4home.com/v1
  • http://{BLOCKED}ates4you.com/v1

Dropping Routine

This backdoor drops the following file(s), into which it saves gathered information:

  • %User Temp%\ss0-{Date}-{Time}-{ms}.sst (Captured Screenshots)
  • %User Temp%\aa0-{Date}-{Time}-{ms}.aat (Captured Audio, WAV)
  • %User Temp%\kk0-{Date}-{Time}-{ms}.kkt (Keylogs)
  • %User Temp%\dd0-{Date}-{Time}-{ms}.ddt (Arbitrary Data)

(Note: %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.)

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.312.03

FIRST VSAPI PATTERN DATE:

02 Feb 2016

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

Identify and terminate files detected as BKDR_MOKES.A

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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
    • {malware dropped copy filename} = "{full path of the dropped copy}"

Step 5

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 dropped copy filepath}\version

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_MOKES.A. 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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