CIS CYBERSECURITY ADVISORIES

MS-ISAC ADVISORY NUMBER:
2015-108

DATE(S) ISSUED:
09/08/2015

SUBJECT:
Cumulative Security Update for Internet Explorer (MS15-094)

OVERVIEW:

Multiple vulnerabilities have been discovered in Microsoft's web browser, Internet Explorer. These vulnerabilities could allow an attacker to execute code in the context of the browser. 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-2015-2542) has been publically disclosed.

SYSTEM AFFECTED:

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

RISK:

Government:

  • 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 that could allow remote code execution. The vulnerabilities are as follows:

  • 13 memory corruption vulnerabilities could allow for remote code execution.
  • One information disclosure vulnerability.
  • One tampering vulnerability.
  • One scripting engine memory corruption vulnerability that could allow for remote code execution.
  • One elevation of privilege vulnerability.

The most severe of these vulnerabilities could allow an attacker to execute remote code by luring a victim to visit a 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.

RECOMMENDATIONS:

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.

REFERENCES:

Microsoft:

https://technet.microsoft.com/library/security/MS15-094

CVE:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2483

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2484

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2485

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2486

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2487

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2489

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2490

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2491

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2492

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2493

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2494

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2498

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2499

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2500

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2501

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2541

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-2542