Trojan.W97M.OSTAP.B

March 16, 2020
 ALIASES:

TrojanDropper:O97M/Powdow!MTB (Microsoft); RDN/Generic Dropper (McAfee)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

396,597 bytes

File Type:

DOCX

Memory Resident:

Yes

Initial Samples Received Date:

16 Mar 2020

Arrival Details

This Trojan 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 Trojan adds the following processes:

  • %System Root%\MyImages\presskey.cmd
  • cscript //nologo %System Root%\MyImages\presskey.jse

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

It creates the following folders:

  • %User Profile%\Application Data\Microsoft\Forms
  • %System Root%\MyImages

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Wow6432Node\Interface\{BEF6E003-A874-101A-8BBA-00AA00300CAB}
(Default) = ""

HKEY_CURRENT_USER\Software\Classes\
Local Settings\Software\Microsoft\
Windows\Shell\Bags\
32\ComDlg
TV_FolderType = "{FBB3477E-C9E4-4B3B-A2BA-D3F5D3CD46F9}"

HKEY_CURRENT_USER\Software\Classes\
Local Settings\Software\Microsoft\
Windows\Shell\Bags\
32\ComDlg
TV_TopViewID = "{82BA0782-5B7A-4569-B5D7-EC83085F08CC}"

HKEY_CURRENT_USER\Software\Classes\
Local Settings\Software\Microsoft\
Windows\Shell\Bags\
32\ComDlg
TV_TopViewVersion = "0"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\Microsoft\Forms\WINWORD.box
  • %System Root%\MyImages\presskey.cmd
  • %System Root%\MyImages\presskey.jse
  • {malware file path and name}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

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

Identify and terminate files detected as Trojan.W97M.OSTAP.B

[ 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 3

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\Classes\Wow6432Node\Interface\{BEF6E003-A874-101A-8BBA-00AA00300CAB}
    • (Default) = ""
  • In HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\Bags\32\ComDlg
    • TV_FolderType = "{FBB3477E-C9E4-4B3B-A2BA-D3F5D3CD46F9}"
  • In HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\Bags\32\ComDlg
    • TV_TopViewID = "{82BA0782-5B7A-4569-B5D7-EC83085F08CC}"
  • In HKEY_CURRENT_USER\Software\Classes\Local Settings\Software\Microsoft\Windows\Shell\Bags\32\ComDlg
    • TV_TopViewVersion = "0"

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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 Profile%\Application Data\Microsoft\Forms\WINWORD.box
  • %System Root%\MyImages\presskey.cmd
  • %System Root%\MyImages\presskey.jse
  • {malware file path and name}

Step 5

Search and delete these folders

[ 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.
  • %User Profile%\Application Data\Microsoft\Forms
  • %System Root%\MyImages

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.W97M.OSTAP.B. 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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