Analysis by: Mohammed Malubay
ALIASES:

Joke:Win32/ScreenMate!MSR(MICROSOFT); a variant of Win32/Joke.ScreenMate.AA potentially unsafe application(NOD32);

 PLATFORM:

Windows

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

  • Threat Type: Joke Program

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Joke Program 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: 299,456 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 Apr 2021

Arrival Details

This Joke Program 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 Joke Program adds the following folders:

  • If [Run on Startup] button was clicked:
    • %Program Files%\ScreenMates\
    • %Start Menu%\Programs\ScreenMates\

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

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

  • If [Run on Startup] button was clicked:
    • %Program Files%\ScreenMates\{Malware Filename}.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It drops the following files:

  • If [Run on Startup] button was clicked:
    • %Start Menu%\Programs\ScreenMates\Puppy.lnk → executes %Program Files%\ScreenMates\{Malware Filename}.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Joke Program adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Puppy = %Program Files%\ScreenMates\{Malware Filename}.exe

Other Details

This Joke Program does the following:

  • Once executed, a puppy animation will appear on the screen.
  • The following buttons will be displayed upon right-clicking on the puppy animation:
    • Stand Still → Makes the puppy stay in one place
    • Always on top → Makes the puppy animation always stay on top of any window
    • Run on Startup → Adds itself to the list of files to be executed on Windows startup
    • Uninstall → Terminates and deletes itself
    • About → Shows brief details regarding the software itself
    • Exit → Terminates itself

  SOLUTION

Minimum Scan Engine: 9.800
SSAPI PATTERN File: 2.395.00
SSAPI PATTERN Date: 25 Mar 2021

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

Restart in Safe Mode

[ Learn More ]

Step 4

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.
  • %Program Files%\ScreenMates\{Malware Filename}.exe
  • %Start Menu%\Programs\ScreenMates\Puppy.lnk

Step 5

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.
  • %Program Files%\ScreenMates\
  • %Start Menu%\Programs\ScreenMates\

Step 6

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
    • Puppy = %Program Files%\ScreenMates\{Malware Filename}.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Joke.Win32.ScreenMate.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.


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