Analysis by: Wilbert Vidal
ALIASES:

Win32.Worm.Sohanad.as (Baidu); Worm.Win32.Sohanad.UY (Comodo)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

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

  TECHNICAL DETAILS

File Size: 244,224 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 29 Jul 2018

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:

  • %Windows%\setting.ini
  • %System%\autorun.ini

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

It drops the following copies of itself into the affected system:

  • %System%\IEXPLORER.exe
  • %System%\WORD.exe

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

Autostart Technique

This Worm modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = Explorer.exe IEXPLORER.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Yahoo Messengger = %System%\IEXPLORER.exe

Propagation

This Worm drops the following copy(ies) of itself in all removable drives:

  • {drive letter}:\IEXPLORER.exe
  • {drive letter}:\Bi mat.exe

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

Dropping Routine

This Worm drops the following files:

  • {removeable drive}:\autorun.inf

Other Details

This Worm connects to the following possibly malicious URL:

  • http://{BLOCKED}tting.{BLOCKED}0mb.com/setting.doc
  • http://{BLOCKED}online.{BLOCKED}m.{BLOCKED}lepages.com/setting.doc
  • http://{BLOCKED}ng3.t35.{BLOCKED}m/setting.doc

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

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.410.04
FIRST VSAPI PATTERN DATE: 29 Jul 2018
VSAPI OPR PATTERN File: 14.411.00
VSAPI OPR PATTERN Date: 30 Jul 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

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = Explorer.exe IEXPLORER.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Yahoo Messengger = %System%\IEXPLORER.exe

Step 5

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%\autorun.ini
  • %Windows%\setting.ini
  • {removeable drive}:\autorun.inf

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_SOHANAD.WIL. 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 7

Scan your computer with your Trend Micro product to delete files detected as WORM_SOHANAD.WIL. 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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