CIS CYBERSECURITY ADVISORIES

MS-ISAC ADVISORY NUMBER:
2015-043

DATE(S) ISSUED:
04/14/2015

SUBJECT:
Multiple vulnerabilities in Microsoft Office Could Allow Remote Code Execution (MS15-033)

OVERVIEW:

Multiple vulnerabilities have been discovered in Microsoft Officethat could allow remote code execution. 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:

Microsoft has reported that CVE-2015-1641 is being exploited in the wild.

SYSTEM AFFECTED:

  • Microsoft Office 2007
  • Microsoft Office 2010
  • Microsoft Office 2013
  • Microsoft Office 2013 RT
  • Microsoft Office for Mac 2011
  • Microsoft Office for Mac for Office 365
  • Microsoft SharePoint Server 2010
  • Microsoft SharePoint Server 2013
  • Microsoft Office Web Apps 2010
  • Microsoft Office Web Apps 2013

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:

Multiple vulnerabilities have been discovered in Microsoft Office which could allow for remote code execution due to the way Microsoft Office parses specially crafted Microsoft Office files.

  • Microsoft Office Memory Corruption Vulnerability (CVE-2015-1641)
  • Microsoft Office Component Use After Free Vulnerability (CVE-2015-1649)
  • Microsoft Office Component Use After Free Vulnerability (CVE-2015-1650)
  • Microsoft Office Component Use After Free Vulnerability (CVE-2015-1651)

One vulnerability has also been discovered in Microsoft Outlook App for Mac that could allow for elevation of privileges.

  • Microsoft Outlook App for Mac XSS Vulnerability (CVE-2015-1639)

Successful exploitation of these vulnerabilities could result in the attacker gaining the same rights 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. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.

RECOMMENDATIONS:

We recommend the following actions be taken:

  • Apply appropriate patches provided by Microsoft to vulnerable systems immediately after appropriate testing.
  • 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.

REFERENCES:

Microsoft:

https://technet.microsoft.com/en-us/security/bulletin/ms15-033

CVE:

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1639

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1641

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1649

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1650

http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1651