Eight Microsoft Security Bulletins are being pushed out this month, MS13-096 through MS13-106. Five of them are rated "Critical" and another six are rated "Important". The top priorities to roll out this month are the critical GDI+ (MS13-096), Internet Explorer (MS13-097), and Scripting Runtime (MS13-099) updates.
Several of the vulnerabilities have been actively exploited as a part of targeted attacks around the world, and one of them is known to be ItW for at least six months or so.
The GDI+ update patches memory corruption vulnerability CVE-2013-3906, which we have been detecting as Exploit.Win32.CVE-2013-3906.a. We have seen a low number of ITW variations on exploitation of this vulnerability as a malformed TIFF file, all dropping backdoors like Citadel, the BlackEnergy bot, PlugX, Taidoor, Janicab, Solar, and Hannover. The target profile and toolset distribution related to these exploit attempts suggest a broad array of likely threat actors that got their hands on it since this July, and a wide reaching distribution chain that provided the exploit around the world. Considering the variety of uses and sources, this one may replace cve-2012-0158 as a part of targeted attacks in terms of overall volume.
The Internet Explorer Bulletin fixes seven different elevation of privilege and memory corruption vulnerabilities, any one of which effects Internet Explorer 6 on Windows XP SP 3 through Internet Explorer 11 on Windows Server 2012 R2 and Windows RT 8.1. We expect to see exploits for some of these vulnerabilities included in commodity exploit packs.
Finally, another critical vulnerability exists in the Windows Scripting Engine as yet another "use after free", which unfortunately enables remote code execution across every version of Windows out there and can be attacked via any of the common web browsers. Patch!
This post will likely be updated later today, but in the meantime, more about this month's patches can be found at the Microsoft site.