A Vulnerability in Microsoft Jscript and VBScript Could Allow for Remote Code Execution (MS16-086)

ITS Advisory Number: 
2016-115
Date(s) Issued: 
Tuesday, July 12, 2016
Subject: 
A Vulnerability in Microsoft Jscript and VBScript Could Allow for Remote Code Execution (MS16-086)
Overview: 

A vulnerability exists in Microsoft Jscript and VBScript engines that could allow for remote code execution if a user visits a specially crafted website. Successful exploitation could result in the attacker gaining the same user rights as the logged on user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. 

Systems Affected: 
  • VBScript 5.7 on Windows Vista installations using Service Pack 2, Windows Server 2008 installations using Service Pack 2

  • Jscript 5.8 and VBScript 5.8 on Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core Installation Only)

RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
Medium
BUSINESS
Large and medium business entities: 
High
Small business entities: 
Medium
Home Users: 
Low
Description: 

A memory corruption vulnerability exists in Microsoft JScript and VBScript engines that could allow for remote code execution if a user visits a specially crafted website. This vulnerability exists in the way these scripting engines render when handling objects in memory for Internet Explorer. This vulnerability could corrupt memory in such a way that an attacker could execute remote code in the context of the current user. (CVE-2016-3204)

 

Successful exploitation could result in the attacker gaining the same user rights as the logged on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

Actions: 
  • After appropriate testing, apply appropriate patches provided by Microsoft to vulnerable systems

  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.

  • Apply the principle of Least Privilege to all systems and services.

  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.

  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from untrusted sources.