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HomeResourcesAdvisoriesCumulative Security Update for Internet Explorer (MS15-106)

Cumulative Security Update for Internet Explorer (MS15-106)

MS-ISAC ADVISORY NUMBER:

2015-121

DATE(S) ISSUED:

10/12/2015

OVERVIEW:

Multiple vulnerabilities have been discovered in Microsoft's web browser, Internet Explorer. The most severe of these vulnerabilities could allow an attacker to execute code in the context of the browser if a user views a specially crafted web page. Successful exploitation of these vulnerabilities could result in an attacker gaining the same privileges 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.

THREAT INTELLIGENCE:

One memory corruption vulnerability (CVE-2015-6056) has been publicly disclosed.

SYSTEMS AFFECTED:

  • Internet Explorer 7
  • Internet Explorer 8
  • Internet Explorer 9
  • Internet Explorer 10
  • Internet Explorer 11

RISK:

Goverment:
  • Large and medium government entities: HIGH
  • Small government entities: HIGH
Businesses:
  • Large and medium business entities: HIGH
  • Small business entities: HIGH
Home Users:
HIGH

TECHNICAL SUMMARY:

Microsoft Internet Explorer is prone to multiple vulnerabilities the most severe of which could allow remote code execution. The vulnerabilities are as follows:

Four memory corruption vulnerabilities could allow for remote code execution.
Three information disclosure vulnerabilities.
Three scripting engine memory corruption vulnerabilities that could allow for remote code execution.
Three elevation of privilege vulnerabilities.
One VBScript and Jscript ASLR Bypass vulnerability.
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.

RECOMENDATIONS:

We recommend the following actions be taken:

Configure Internet Explorer to prompt before running Active Scripting or disable Active Scripting in the Internet and local intranet security zone until a patch is released.
Apply updates as soon as possible after appropriate testing.
Remind users not to visit 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 from untrusted sources.

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