BKDR_PLEAD.SMZTDK-A

February 22, 2018
 Analysis by: Michael Jay Villanueva
 ALIASES:

Trojan:Win32/Harmony.A!dha (Microsoft)

 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 as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It does not have any propagation routine.

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:

442,368 bytes

Memory Resident:

Yes

Initial Samples Received Date:

18 Jan 2018

Payload:

Connects to URLs/IPs

Arrival Details

This Backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 the following copies of itself into the affected system:

  • %Application Data%\Microsoft\search.exe -> attributes are set to Hidden, System, and Archive

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Switch Board = %Application Data%\Microsoft\search.exe

Propagation

This Backdoor does not have any propagation routine.

Backdoor Routine

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

  • Executes arbitrary commands

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

  • http://{BLOCKED}.{BLOCKED}list.com/Default.aspx
  • http://{BLOCKED}s.{BLOCKED}info.com/Default.aspx

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

Rootkit Capabilities

This Backdoor does not have rootkit capabilities.

Other Details

This Backdoor does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.164.08

FIRST VSAPI PATTERN DATE:

18 Jan 2017

VSAPI OPR PATTERN File:

13.165.80

VSAPI OPR PATTERN Date:

19 Jan 2017

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

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\Run
    • Switch Board = %Application Data%\Microsoft\search.exe

Step 5

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

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_PLEAD.SMZTDK-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 the following Trend Micro Support pages for more information:


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