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Trojan.Win32.DOWNLOADER.T

May 06, 2024
 Analysis by: Leidryn Saludez
 ALIASES:

UDS:Trojan-Downloader.Win32.OffLoader.gen (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

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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:

1,767,129 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

16 Apr 2024

Payload:

Connects to URLs/IPs, Drops files, Modifies system registry

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:

  • %User Temp%\is-{Random}.tmp\{Malware File Name}.tmp
  • %User Temp%\is-{Random}.tmp\idp.dll

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

It adds the following processes:

  • %User Temp%\is-{Random}.tmp\Malware File Name}.tmp

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

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
Owner = 34 0A 00 00 C8 2E 0C 33 5E 9F DA 0

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
SessionHash = C1 BC 42 BF 01 0C DA D4 E5 AA 04 A7 E5 5D 0D C5 C7 98 E5 CC 80 8D 14 E5 CE 61 73 7A 14 A4 61 F9

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
Sequence = 1

Other Details

This Trojan connects to the following possibly malicious URL:

  • https://{BLOCKED}ont.xyz/fi.php?pid=4033&tid=49091169&a=4033&cc=TW&t=1711595135

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

19.316.03

FIRST VSAPI PATTERN DATE:

03 May 2024

VSAPI OPR PATTERN File:

19.317.00

VSAPI OPR PATTERN Date:

04 May 2024

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.XXPE50FSX046

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 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\RestartManager\Session0000
    • Owner = 34 0A 00 00 C8 2E 0C 33 5E 9F DA 0
  • In HKEY_CURRENT_USER\Software\Microsoft\RestartManager\Session0000
    • SessionHash = C1 BC 42 BF 01 0C DA D4 E5 AA 04 A7 E5 5D 0D C5 C7 98 E5 CC 80 8D 14 E5 CE 61 73 7A 14 A4 61 F9
  • In HKEY_CURRENT_USER\Software\Microsoft\RestartManager\Session0000
    • Sequence = 1

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.
  • %User Temp%\is-{Random}.tmp\{Malware File Name}.tmp
  • %User Temp%\is-{Random}.tmp\idp.dll

Step 6

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.DOWNLOADER.T. 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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