In May's Patch Tuesday, the fixes provided by Microsoft mostly target client-sided applications, along with a fix for a server-sided component. These 10 patches address 33 vulnerabilities in Internet Explorer (including the recent 0day), .NET, Lync, Publisher, Word, Visio, Windows Essentials, Kernel mode drivers, and the HTTP.sys component.
Two patches were released this month for Internet Explorer. The first bulletin, MS13-037, affects every version of Internet Explorer, 6 through 10, and therefore affects every version of Windows. 10 use after free vulnerabilities were addressed, along with an information disclosure vulnerability. Three of the CVEs, CVE-2013-1308, CVE-2013-1309, and CVE-2013-2551, affect every version as well, so attackers will likely be focusing on those CVEs in an attempt to target as broad of an audience as possible with the least amount of effort as is needed. The second bulletin, MS13-038, addresses the Internet Explorer 0day that was publicly disclosed on May 3rd. Take note that while no known attack vectors exist for Internet Explorer 9 in the default configuration, the vulnerable component still exists and is therefore receiving an update.
The next bulletin, MS13-039, addresses a privately reported denial of service vulnerability in Windows 8, Server 2012, and RT. This is possible by simply sending a specially crafted HTTP header to a vulnerable server, causing it to go into an infinite loop. Attackers will be interested in this vulnerability because it affects the latest versions of Windows Server and can trivially be exploited by attackers. Even though this bulletin is only rated as important, it should be patched immediately, since attackers will likely start to leverage this vulnerability as soon as possible.
And what's a good Patch Tuesday without a little bit of .NET sprinkled in? Microsoft's got you covered with that in MS13-040, fixing two vulnerabilities: an XML digital signature spoofing vulnerability and an authentication bypass vulnerability. The signature spoofing vulnerability affects multiple versions of .NET (2.0 SP2, 3.5, 3.5.1, 4.0, and 4.5), while the authentication bypass vulnerability only affects version 4.5.
This month's patch cycle addresses many Office-related vulnerabilities. MS13-041 addresses a privately reported use after free vulnerability in Lync. MS13-042 addresses 11 privately reported remote code execution vulnerabilities in Publisher 2003, 2007, and 2010 (2013 is unaffected). MS13-043 fixes a vulnerability in Word 2003 that is triggered when parsing certain shape data in a specially crafted Word file. MS13-044 addresses an information disclosure vulnerability in Visio 2003, 2007, and 2010 (2013 is unaffected), which could be used to read files from the targeted system.
Windows Essentials received a patch this month in MS13-045, fixing an information disclosure that could allow an attacker to override Windows Writer proxy settings and overwrite any files the user has access to on the system. While both Windows Essentials 2011 and 2012 are affected, only Windows Essentials 2012 is receiving updates. Therefore, if you are using Windows Essentials 2011, it is very highly recommended that you upgrade to Windows Essentials 2012, so that you can continue receiving security updates.
Lastly, MS13-046 closes out the month with a fix for three privately reported local elevation of privilege vulnerabilities in Windows Kernel mode drivers. The most severe of these vulnerabilities, CVE-2013-1334, only affects Windows XP, allowing an attacker to run processes in an elevated context.
Be sure to patch Internet Explorer (MS13-037 and MS13-038) as soon as possible, along with MS13-039 on internet-facing web servers, followed by the rest of the patches. Also, be sure to join us for the Vulnerability Expert Forum tomorrow, Wednesday, April 15 at 1pm PT, where we cover these patches, as well as other security news. Sign up here.
