CIS CYBER SECURITY ADVISORIES

MS-ISAC CYBER SECURITY ADVISORY NUMBER:
2014-027

DATE(S) ISSUED:
03/24/2014
04/08/2014 - Updated

SUBJECT:
Memory Corruption Vulnerability in Microsoft Word Could Allow Remote Code Execution

ORIGINAL OVERVIEW:

A memory corruption vulnerability has been discovered in Microsoft Word that could allow for remote code execution. An attacker can exploit this issue to execute arbitrary code in the context of the currently logged-in user. Failed exploit attempts will likely result in denial-of-service conditions.

UPDATED EXECUTIVE SUMMARY:
Microsoft has issued a patch for this vulnerability and included it in security bulletin MS14-017.

THREAT INTELLIGENCE:
According to a post on Microsoft Security Research and Defense Blog, this vulnerability is actively being exploited in targeted attacks directed at Microsoft Word 2010. These targeted attacks take advantage of the RTF parsing vulnerability and an Address Space Layout Randomization (ASLR) bypass which depends on a module loaded at a predictable memory address. The blog posting mentions that the Enhanced Mitigation Experience Toolkit (EMET) default configuration was tested against this attack and was found to effectively stop the exploit attempt. Please see http://blogs.technet.com/b/srd/archive/2014/03/24/security-advisory-2953095-recommendation-to-stay-protected-and-for-detections.aspx for the rest of the blog posting.

SYSTEMS AFFECTED:

  • Microsoft Office 2007
  • Microsoft Office 2010
  • Microsoft Office 2013
  • Microsoft Office Compatibility Pack SP3

 

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:
A memory corruption vulnerability has been discovered in Microsoft Word that could allow for remote code execution. Specificaly, this issue occurs when Microsoft Word parses a specially crafted Rich Text Format (RTF) file. To exploit this issue, an attacker would need to entice an unsuspecting user to view the specially crafted RTF file. Successful exploitation of this vulnerability will allow attackers to execute arbitrary code in the context of the currently logged-in user. Failed exploit attempts will likely result in denial-of-service conditions.

RECOMMENDATIONS:
We recommend the following actions be taken:

  • Microsoft has released a security advisory regarding this vulnerability and has provided a "Fix it" solution which makes it impossible for Microsoft Word to open RTF files. This will prevent the exploitation of this vulnerability. See http://technet.microsoft.com/en-us/security/advisory/2953095 for more information about this solution.
  • 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 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 un-trusted sources.

 

UPDATED RECOMMENDATIONS:

  • Install the updates provided by Microsoft immediately after appropriate testing.

 

REFERENCES:
Microsoft:

http://technet.microsoft.com/en-us/security/advisory/2953095
http://blogs.technet.com/b/srd/archive/2014/03/24/security-advisory-2953095-recommendation-to-stay-protected-and-for-detections.aspx
http://technet.microsoft.com/en-us/security/jj653751 - Enhanced Mitigation Experience Toolkit (EMET)

SecurityFocus:

http://www.securityfocus.com/bid/66385

CVE:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-1761

UPDATED REFERENCES:
Microsoft:
https://technet.microsoft.com/en-us/security/bulletin/ms14-017