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TROJ_CVE20178759.A

August 01, 2018
 Analysis by: Johnlery Triunfante
 Modified by: Jennifer Gumban
 ALIASES:

Exploit:Win32/CVE-2017-8759.A (MICROSOFT); Exploit.MSOffice.CVE-2017-8759.a (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


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

Once a malware successfully exploits the said vulnerability, it causes certain actions to be done on the system. It takes advantage of certain vulnerabilities. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

52,911 bytes

File Type:

RTF

Memory Resident:

No

Initial Samples Received Date:

12 Sep 2017

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.

Installation

This Trojan adds the following processes:

  • mshta.exe

Download Routine

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

  • http://{BLOCKED}.{BLOCKED}.236.207/img/left.jpg

Trend Micro detects the dowloaded file as:

  • TSPY_FINSPY.A

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

Other Details

Once a malware successfully exploits the said vulnerability, it causes the following actions to be done on the system:

  • Creates new process to download script file detected as TROJ_POWLOAD.ASUKQ from http://{BLOCKED}.{BLOCKED}.236.207/img/word.db

It takes advantage of the following vulnerabilities:

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

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.656.03

FIRST VSAPI PATTERN DATE:

13 Sep 2017

VSAPI OPR PATTERN File:

13.657.00

VSAPI OPR PATTERN Date:

14 Sep 2017

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 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

Remove the malware/grayware file dropped/downloaded by TROJ_CVE20178759.A. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     
    • TROJ_POWLOAD.ASUKQ
    • TSPY_FINSPY.A

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CVE20178759.A. 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 this Knowledge Base page for more information.


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