Analysis by: Arvin Roi Macaraeg
ALIASES:

HEUR:Exploit.MSOffice.Generic (Kaspersky)

 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

Infection Channel: Spammed via email, Dropped by other malware, Downloaded from the Internet

It takes advantage of software vulnerabilities to allow a remote user or malware/grayware to download files.

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It 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 downloaded files whose malicious routines are exhibited by the affected system.

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

  TECHNICAL DETAILS

File Size: 56,904 bytes
File Type: XLSX
Memory Resident: No
Initial Samples Received Date: 01 Aug 2019
Payload: Connects to URLs/IPs, Downloads files, Exploits vulnerability

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 downloads the file from the following URL and renames the file when stored in the affected system:

  • http://serverstresstestgood.{BLOCKED}s.org/big/big.exe

It takes advantage of the following software vulnerabilities to download possibly malicious files:

It executes downloaded files :

  • %User%\s.exe
whose malicious routines are exhibited by the affected system.

Other Details

This Trojan does the following:

  • The document contains either of the following message details luring users to enable macro content:

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

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.272.02
FIRST VSAPI PATTERN DATE: 02 Aug 2019
VSAPI OPR PATTERN File: 15.273.00
VSAPI OPR PATTERN Date: 02 Aug 2019

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.
  • %User%\s.exe

Step 4

Scan your computer with your Trend Micro product to delete files detected as Trojan.X97M.CVE201711882.PVSER. 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 this security patch 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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