BKDR_BZUB.KZ

 Analysis by: Rika Joi Gregorio

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


This backdoor may arrive as a file that exports functions used by other malware. It may be dropped by other malware.

It deletes registry entries, causing some applications and programs to not function properly.

It does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It does not have any downloading capability.

  TECHNICAL DETAILS

File Size:

32,768 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

23 Aug 2013

Arrival Details

This backdoor may arrive as a file that exports functions used by other malware.

It may be dropped by other malware.

Installation

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

  • %User Temp%\{random digit}.dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

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

  • GDGSYDLYR_1848874853

Other System Modifications

This backdoor deletes the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
6E339765 =

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Upload file
  • Perform remote shell commands

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

  • http://{BLOCKED}.{BLOCKED}.228.102:443/info.asp

Download Routine

This backdoor does not have any downloading capability.

Information Theft

This backdoor gathers the following data:

  • Host Name
  • User Name
  • Drive and volume information

NOTES:

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.244.03

FIRST VSAPI PATTERN DATE:

28 Aug 2013

VSAPI OPR PATTERN File:

10.245.00

VSAPI OPR PATTERN Date:

29 Aug 2013

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

Scan your computer with your Trend Micro product and note files detected as BKDR_BZUB.KZ

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete the files detected as BKDR_BZUB.KZ

*Note: Some component files may be 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.

To stop the malware/grayware from running when certain files are opened:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Right-click Start then click Search....
  2. In the Named input box, type the name of the file that was detected earlier.
  3. In the Look In drop-down list, select My Computer then press Enter.
  4. Once located, select the file then press SHIFT+DELETE to delete it.

For Windows Vista and Windows 7:

  1. Click Start>Computer.
  2. In the Search Computer input box, type the name of the file detected earlier, and press Enter.
  3. Once located, select the file then press SHIFT+DELETE to delete it.
    *Note: Read the following Microsoft page if these steps do not work on Windows 7.

Step 5

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