Trojan.JS.DLOADR.AUSUNU

March 20, 2020
 Analysis by: Bren Matthew Ebriega
 ALIASES:

Trojan:Win32/Bluteal!rfn (MICROSOFT); JS/Agent.UPK!tr.dldr (FORTINET)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

44,971 bytes

File Type:

JS

Memory Resident:

No

Initial Samples Received Date:

17 Mar 2020

Payload:

Connects to URLs/IPs, Downloads files

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.

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}lf55home.ru/main/tpc.exe

It saves the files it downloads using the following names:

  • %Application Data%\Microsoft\Windows\Templates\{6-random chars}.exe

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

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.748.03

FIRST VSAPI PATTERN DATE:

17 Mar 2020

VSAPI OPR PATTERN File:

15.749.00

VSAPI OPR PATTERN Date:

18 Mar 2020

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

Search and delete these files

[ 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.  
  • %Application Data%\Microsoft\Windows\Templates\{6-random chars}.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.JS.DLOADR.AUSUNU. 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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