BKDR_SAKUREL.D

 Analysis by: David John Agni

 ALIASES:

Trojan.Win32.Sakelua.a (Kaspersky), TrojanDropper:Win32/Derusbi!dha (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:

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

It gathers certain information on the affected computer.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

508,128 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Jun 2015

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 and executes the following files:

  • %User Temp%\Center6195548.dat - detected as BKDR_SAKUREL.D
  • %User Temp%\MicroMedia\MediaCenter.exe - detected as BKDR_SAKUREL.D

(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.)

It creates the following folders:

  • %User Temp%\MicroMedia

(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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
MicroMedia = "%User Temp%\MicroMedia\MediaCenter.exe"

Backdoor Routine

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

  • Perform Remote Shell Command
  • Download and execute file
  • Open and Read File
  • Execute File
  • Uninstall Itself
  • Send Malware Process ID

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

  • http://www.{BLOCKED}int.com:443/photo/qlvgtjvadtkec-{Volume Serial Number}.jpg?vid={random number}
  • http://www.{BLOCKED}int.com:443/view.asp?cookie=qlvgtjvadtkec-{Volume Serial Number}&type=0&vid={random number}

Download Routine

This backdoor saves the files it downloads using the following names:

  • %User Temp%\{random filename}.tmp.exe

(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.)

Information Theft

This backdoor gathers the following information on the affected computer:

  • Volume Serial Number

Other Details

However, as of this writing, the said sites are inaccessible.

NOTES:

It executes the following commands if only it found itself not running with administrative privileges:

  • cmd.exe /c rundll32 "%User Temp%\{random file name}.tmp"Play "%User Temp%\MicroMedia\MediaCenter.exe"
  • %User Temp%\{random filename}.tmp - detected as HKTL_GOADMIN.GA

  SOLUTION

Minimum Scan Engine:

9.750

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_SAKUREL.D

[ 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • MicroMedia = "%User Temp%\MicroMedia\MediaCenter.exe"

Step 5

Remove malware/grayware files dropped/downloaded by BKDR_SAKUREL.D. (Note: Please skip this step if the threats listed below have already been removed.)

    • HKTL_GOADMIN.GA

Step 6

Search and delete these folders

[ 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.
  • %User Temp%\MicroMedia

Step 7

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.
  • %User Temp%\MicroMedia\MediaCenter.exe
  • %User Temp%\Center6195548.dat
  • %User Temp%\{random filename}.tmp.exe

Step 8

Scan your computer with your Trend Micro product to delete files detected as BKDR_SAKUREL.D. 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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