Worm.Win32.HERMWIZ.YECCA

 Analysis by: Arianne Grace Dela Cruz

 ALIASES:

DoS:Win32/FoxBlade.A!dha (MICROSOFT); Win32/Agent.OJC worm (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Worm 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:

698,632 bytes

File Type:

DLL

Memory Resident:

No

Initial Samples Received Date:

01 Mar 2022

Arrival Details

This Worm 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 Worm drops the following files:

  • Once it establishes a connection to an IP within its network:
    • {Malware File Path}\{Random 2}.ocx - module used for SMB propagation and execution to the remote machine
    • {Malware File Path}\{Random 3}.ocx - module used for WMI propagation and execution to the remote machine
  • {Malware File Path}\{c{12 Random Characters}}.dll - copy of itself

It drops and executes the following files:

  • {Malware File Path}\{Random 1}.ocx - Disk Wiper

It adds the following processes:

  • Once a connection to an IP address is established:
    • %System%\regsvr32.exe {Malware File Path}\{Random 2}.ocx #1 -s {Malware File Path}\{c{12 Random Characters}}.dll -i {Target IP Address}
    • %System%\regsvr32.exe {Malware File Path}\{Random 3}.ocx #1 -s {Malware File Path}\{c{12 Random Characters}}.dll -i {Target IP Address}

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

Propagation

This Worm drops the following file(s) in remote admin shares:

  • \{IP Address}\ADMIN$\{Malware File Path}\{c{12 Random Characters}}.dll

Other Details

This Worm does the following:

  • It obtains IP addresses within the local network via:
    • Obtaining the physical address mapping table
    • Enumerating servers in the domain
    • Obtaining the TCP Table
    • Adapters addresses
  • It tries to establish a connection on the IP addresses obtained and copy itself remotely.

It accepts the following parameters:

  • -s --> allows full scanning of IP addresses found using the following ports:
    • 20
    • 21
    • 22
    • 80
    • 135
    • 137
    • 139
    • 443
    • 445

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

17.414.08

FIRST VSAPI PATTERN DATE:

01 Mar 2022

VSAPI OPR PATTERN File:

17.415.00

VSAPI OPR PATTERN Date:

02 Mar 2022

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

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

Identify and terminate files detected as Worm.Win32.HERMWIZ.YECCA

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

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.  
  • {Malware File Path}\{Random 1}.ocx
  • {Malware File Path}\{Random 2}.ocx
  • {Malware File Path}\{Random 3}.ocx
  • {Malware File Path}\{c{12 Random Characters}}.dll

Step 5

Scan your computer with your Trend Micro product to delete files detected as Worm.Win32.HERMWIZ.YECCA. 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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