BKDR64_WINNTI.CH

 Analysis by: Homer Pacag
 Modified by: Jeanne Jocson

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

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.

  TECHNICAL DETAILS

File Size:

184,832 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

07 Jul 2016

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.

Dropping Routine

This backdoor drops the following files:

  • %System%\assocnet.inf

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other Details

This backdoor does the following:

  • Copies the file time of calc.exe or mspaint.exe
  • Queries Volume Information
  • Enumerates active session
  • Adjust Privilege
  • GetComputerName
  • UserName
  • System's Locale
  • Get OS version
  • GetMemory Status
  • Backdoor Commands:
    • Gathers the following:
      • Drive name
        Drive Type
        Volume name
        Total number of bytes available
        Total number of bytes
    • Search Files and gets the following:
      • Creation Time
        Last AccessTime
        Last Write Time
        File Attributes
    • Move file to following:
      • {path}\{Folder name}\{random numbers1}-{random numbers2}-{random numbers3}-{random numbers4}.bak
        %System%\{random numbers1}-{random numbers2}-{random numbers3}-{random numbers4}.bak
    • Create Temp File %User Temp%\PCH{tempname}
    • Connect to an IP
    • Execute File
    • Drop INF file
    • Execute commands
    • Elevate Privilage

    (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.)

    NOTES:

    This backdoor requires its main component to register this malware as a service.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.636.03

FIRST VSAPI PATTERN DATE:

07 Jul 2016

VSAPI OPR PATTERN File:

12.637.00

VSAPI OPR PATTERN Date:

08 Jul 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

Remove the malware/grayware file dropped/downloaded by BKDR64_WINNTI.CH. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    %System%\assocnet.inf

Step 4

Scan your computer with your Trend Micro product to delete files detected as BKDR64_WINNTI.CH. 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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