Analysis by: Paul Steven Nadera
ALIASES:

HEUR:Exploit.RTF.CVE-2018-0802.gen (Kaspersky); Exploit:O97M/DDEDownloader.T (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Canal de infección Downloaded from the Internet

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

Tamaño del archivo 229,802 bytes
Tipo de archivo RTF
Residente en memoria No
Fecha de recepción de las muestras iniciales 06 Nov 2020

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%\8.t -> detected as Trojan.Win32.POISONVY.YPAL-ENC

(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:

  • {Parent Process Name}.exe

It injects codes into the following process(es):

  • {Parent Process Name}.exe

Other Details

This Trojan does the following:

  • Patches "msvcrt.clearerr" API with malicious shellcode for stealth

It takes advantage of the following exploit(s):

  SOLUTION

Motor de exploración mínimo 9.800
Primer archivo de patrones de VSAPI 16.334.04
Primera fecha de publicación de patrones de VSAPI 06 Nov 2020
Versión de patrones OPR de VSAPI 16.335.00
Fecha de publicación de patrones OPR de VSAPI 07 Nov 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 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%\8.t

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.W97M.CVE20180798.ZYHK. 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:

Step 5

Download and apply these security patches Refrain from using these products until the appropriate patches have been installed. Trend Micro advises users to download critical patches upon release by vendors.


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