BKDR_REDLEAVES.ZLFC-A

April 17, 2018
 Analysis by: John Anthony Banes
 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:

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 may be dropped by other malware.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

425,984 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

16 Apr 2018

Payload:

Drops files, Connects to URLs/IPs

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 dropped by the following malware:

  • W2KM_REDLEAVES.NVE

Installation

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

  • e(56109H!

Autostart Technique

This Backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\CmrcFFHet.lnk - points to non-malicious executable (VizorHtmlDialog.exe) that loads this malicious DLL file.

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Backdoor Routine

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

  • Execute commands using command prompt
  • System Information
    • Operating System Version
    • System Type (32-bit or 64-bit)
    • Memory
    • Language
    • Computer name
    • IP Address
  • Update C2 configuration
  • Upload/Download files

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

  • http://{BLOCKED}tikhonova.{BLOCKED}.org/index.php

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

Other Details

This Backdoor requires the existence of the following files to properly run:

  • VizorHtmlDialog.exe - non-malicious file that loads this malicious DLL.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.142.02

FIRST VSAPI PATTERN DATE:

21 Mar 2018

VSAPI OPR PATTERN File:

14.143.00

VSAPI OPR PATTERN Date:

22 Mar 2018

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 that dropped/downloaded BKDR_REDLEAVES.ZLFC-A. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    • W2KM_REDLEAVES.NVE

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete these files

[ 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 Startup%\CmrcFFHet.lnk

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_REDLEAVES.ZLFC-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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