Cumulative Security Update for Internet Explorer (MS16-051)

ITS Advisory Number: 
2016-083
Date(s) Issued: 
Tuesday, May 10, 2016
Subject: 
Cumulative Security Update for Internet Explorer (MS16-051)
Overview: 

Multiple vulnerabilities have been discovered in Microsoft Internet Explorer. These vulnerabilities could allow an attacker to execute code in the context of the browser if a user views a specially crafted web page. An attacker who successfully exploited the vulnerabilities could gain the same user rights as the current 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.

Systems Affected: 
  • Internet Explorer 11
  • Internet Explorer 10
  • Internet Explorer 9
RISK
GOVERNMENT
Large and medium government entities: 
High
Small government entities: 
High
BUSINESS
Large and medium business entities: 
High
Small business entities: 
High
Home Users: 
High
Description: 

Microsoft Internet Explorer is prone to multiple vulnerabilities that could allow remote code execution. The vulnerabilities are as follows:

  • Multiple memory corruption vulnerabilities exist in the way Jscript and VBScript engines render when handling objects in memory (CVE-2016-0187,CVE-2016-0189)
  • A security feature bypass vulnerability exists in the UMCI component of Device Guard when it improperly validates code integrity (CVE-2016-0188)
  • A memory corruption vulnerability when Internet Explorer improperly accesses objects in memory (CVE-2016-0192).
  • An information disclosure vulnerability exists when Internet Explorer does not properly handle file access permissions (CVE-2016-0194).

The most severe of these vulnerabilities could allow an attacker to execute remote code by luring a victim to visit a specially crafted malicious website. When the website is visited, the attacker's script will run within the context of the affected browser or with the same permissions as the affected user account. 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.
  • Consider implementing the workarounds provided by Microsoft if patching cannot be completed immediately, see the Microsoft link in the references section below.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • Remind users not to visit untrusted websites or follow links provided by unknown or untrusted sources.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments, especially those from un-trusted sources.