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Backdoor.Win32.ZEGOST.WLDD

May 12, 2020
 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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:

200,168 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 May 2020

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.

Installation

This Backdoor creates the following folders:

  • %System Root%\Program Files\AppPatch

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

Other System Modifications

This Backdoor adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Wsfekv knhhogjj
ConnectGroup = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Wsfekv knhhogjj
MarkTime = "2020-01-08 20:40"

Dropping Routine

This Backdoor drops the following files:

  • %System Root%\Program Files\AppPatch\NetSyst96.dll

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

Other Details

This Backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}192.55/NetSyst96.dll
  • http://www.{BLOCKED}8.com/ips138.asp?ip=42.51.192.55&action=2

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Wsfekv knhhogjj
    • ConnectGroup = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Wsfekv knhhogjj
    • MarkTime = "2020-01-08 20:40"

Step 3

Search and delete this file

[ 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.
  • %System Root%\Program Files\AppPatch\NetSyst96.dll

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\Program Files\AppPatch

Step 5

Scan your computer with your Trend Micro product to delete files detected as Backdoor.Win32.ZEGOST.WLDD. 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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