CIS CYBER SECURITY ADVISORIES

MS-ISAC CYBER SECURITY ADVISORY NUMBER:
2013-044

DATE(S) ISSUED:
05/04/2013, 05/09/2013 - Updated 05/14/2013 - Updated

SUBJECT:
Vulnerability in Internet Explorer Could Allow Remote Code Execution

ORIGINAL OVERVIEW:

A vulnerability has been discovered in Microsoft's web browser, Internet Explorer, which could allow an attacker to take complete control of an affected system. Exploitation may occur if a user visits or is redirected to a web page which is specifically crafted to take advantage of the vulnerability. Successful exploitation of this vulnerability 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. Failed exploit attempts may result in a denial-of-service condition.

It should be noted that there is currently no patch available for this vulnerability and it is currently being exploited in the wild.

May 9 - UPDATED OVERVIEW:
Microsoft has released a workaround which acts a temporary fix for this issue.


It should be noted that there is still no patch available for this vulnerability.

May 14 - UPDATED OVERVIEW:
Microsoft has released a patch for this vulnerability.

SYSTEMS AFFECTED:

  • Internet Explorer 8

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

DESCRIPTION:

A vulnerability has been discovered in Microsoft's web browser, Internet Explorer, which could allow an attacker to take complete control of an affected system. The vulnerability occurs due to Internet Explorer improperly handling a condition where a deleted object is accessed. This may result in a use-after-free condition and lead to execution of arbitrary code. A use-after-free condition occurs when Internet Explorer accesses an object in memory that was already freed.

Exploitation may occur if a user visits or is redirected to a web page which is specifically crafted to take advantage of this vulnerability. Successful exploitation of the vulnerability 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. Failed exploit attempts may result in a denial-of-service condition.

It should be noted that there is currently no patch available for this vulnerability and it is currently being exploited in the wild.

May 9 - UPDATED DESCRIPTION:
Microsoft has released a workaround which acts a temporary fix for this issue until a patch is released. This fix is available at: https://support.microsoft.com/kb/2847140

May 14 - UPDATED DESCRIPTION
Microsoft has released a patch for this vulnerability and it can be found at https://technet.microsoft.com/en-us/security/bulletin/ms13-038

RECOMMENDATIONS:

We recommend the following actions be taken:

  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.
  • If you have an alternate browser deployed, consider using it until this vulnerability is remediated.
  • Consider deploying the Enhanced Mitigation Experience Toolkit.
  • Consider setting Internet and Local intranet security zone settings to 'High' to block ActiveX Controls and Active Scripting in these zones.
  • Consider configuring Internet Explorer to prompt before running Active Scripting or disable Active Scripting in the Internet and Local intranet security zone.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from un-trusted sources.

MAY 14 - UPDATED RECOMMENDATIONS:
Upgrade to the most recent version of Internet Explorer or apply the update provided by Microsoft immediately after appropriate testing.

REFERENCES:

Microsoft:

http://technet.microsoft.com/en-us/security/advisory/2847140

CVE:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-1347

SecurityFocus:

http://www.securityfocus.com/bid/59641

May 9 - UPDATED REFERENCES
Microsoft:
https://support.microsoft.com/kb/2847140

May 14 - UPDATED REFERENCES
Microsoft:
https://technet.microsoft.com/en-us/security/bulletin/ms13-038