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BKDR64_BLYPT.B

October 03, 2013
 Analysis by: Adrian Cofreros
 PLATFORM:

Windows XP (64-bit), Windows Vista (64-bit), Windows 7 (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

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 may be downloaded from remote sites by other malware.

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

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

124,917 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

21 Sep 2013

Payload:

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.

It may be downloaded from remote site(s) by the following malware:

  • BKDR_BLYPT.A

Installation

This backdoor injects codes into the following process(es):

  • explorer.exe

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\RunOnce
CryptoUpdate = ""%SystemRoot%\system32\rundll32.exe "{malware file name and path}",Crypt"

Backdoor Routine

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

  • Updates the dll binary file
  • Receives and executes arbitrary code
  • Updates C&C configuration the following registry key:
    HKEY_CURRENT_USER\Software\Microsoft\SystemCertificates\CA\Certificates\5A82739996ED9EBA18F1BBCDCCA62D2C1D670C

Information Theft

This backdoor retrieves the following information from the affected system:

  • Native System Information

NOTES:

Its component will initially provide initial list of the C&C.

It sends installation status reports with the following format to its C&C server:

GET /index.aspx?info={defined status keyword}

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.290.08

FIRST VSAPI PATTERN DATE:

21 Sep 2013

VSAPI OPR PATTERN File:

10.291.00

VSAPI OPR PATTERN Date:

21 Sep 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

Remove malware/grayware files that dropped/downloaded BKDR64_BLYPT.B

Step 3

Restart in Safe Mode

[ Learn More ]

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\RunOnce
    • CryptoUpdate = ""%SystemRoot%\system32\rundll32.exe "{malware file name and path}",Crypt"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR64_BLYPT.B. 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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