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PUA.Win32.Safebytes.A

May 26, 2023
 Analysis by: Melvin Jhun Palbusa
 ALIASES:

Riskware/DllKitster (FORTINET)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This Potentially Unwanted Application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

904,176 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

22 May 2023

Payload:

Connects to URLs/IPs, Modifies system registry, Displays message/message boxes

Arrival Details

This Potentially Unwanted Application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Other System Modifications

This Potentially Unwanted Application adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
(Default) = (value not set)

HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
DllName = Api-ms-win-crt-runtime-|1-1-0.dll

HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
DownloadID = usrid_7d8b6d1d-testmo_b-cid_dllkit-dll.TX.001_f731_api-ms-win-crt-runtime-|1-1-0.dll-filename_api-ms-win-crt-runtime-|1-1-0

HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
LanguageCode = en

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO

Download Routine

This Potentially Unwanted Application connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.79/dllkit_fullsetup.exe
  • http://{BLOCKED}.{BLOCKED}.{BLOCKED}.170/dllkit_fullsetup.exe

As of this writing, the said sites are inaccessible.

Other Details

This Potentially Unwanted Application does the following:

  • It displays the following during installation:

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

2.627.00

FIRST VSAPI PATTERN DATE:

26 May 2023

VSAPI OPR PATTERN File:

2.627.00

VSAPI OPR PATTERN Date:

27 May 2023

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     TSPY.Win32.TRX.XXPE50FFF068

Step 2

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 3

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 4

Delete this registry key

[ 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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\
    • DllKitPRO

Step 5

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\DllKitPRO
    • (Default) = (value not set)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
    • DllName = Api-ms-win-crt-runtime-|1-1-0.dll
  • In HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
    • DownloadID = usrid_7d8b6d1d-testmo_b-cid_dllkit-dll.TX.001_f731_api-ms-win-crt-runtime-|1-1-0.dll-filename_api-ms-win-crt-runtime-|1-1-0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\DllKitPRO
    • LanguageCode = en


Step 6

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.Safebytes.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 the following Trend Micro Support pages for more information:


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