Blog: Microsoft Updates September 2013 - Critical Server and Client Side RCE Vulnerabilities in IE, Outlook, Built-in Windows Components and Sharepoint

Microsoft releases a long list of security bulletins this month on the server and client side, patching a longer list of vulnerabilities in this month's array of technologies. Only four of the bulletins are rated "critical" this month: Internet Explorer, a variety of built-in Windows components, and Sharepoint and Office Web Services. Thirteen security bulletins are released in total, patching almost fifty vulnerabilities. Mostly every one of this month's vulnerabilities were reported privately, other than the XSS vulnerability in Sharepoint, which Microsoft claims would be difficult to exploit. In all likelihood, at some point Windows folks will have to reboot following download and install of around 100Mb of system updates this month.

For mass exploitation purposes, the most problematic issues have to do with Internet Explorer, with working exploits likely being developed in the near future to attack these memory corruption vulnerabilities. These are the sort of things that can happen to anyone online, so all Windows users should address them asap. These ten vulnerabilities enable remote code execution across all supported versions of IE across all Windows clients and servers, so most likely, they will receive immediate attention from the offensive security global peanut gallery.

On the targeted attack side, Sharepoint and Web Office Service administrators need to be aware of the critical vulnerabilities addressed with the large cumulative update MS013-067. Flaws in this code base enable RCE that could be exploited with the spear phishing techniques very commonly and effectively in use.

Also problematic from both perspectives is this interesting Outlook update, which patches a flaw in Outlook 2007 and 2010 S/MIME handling. It can be triggered in preview mode, which seems to make this the first severe, potentially wormable issue seen in Outlook in years. Patch immediately.

The long list of important updates are presented at Microsoft's Technet site here.

Blog: Microsoft Updates August 2013 - Critical Internet Explorer across All Windows Clients, OpenType Font Parsing, Exchange OWA Vulnerabilities Fixed

Today, Microsoft released a set of eight security Bulletins (MS13-059 through MS13-066) for a broad variety of vulnerable technologies and exploit categories. The critical vulnerabilities are not known to be exploited publicly at the time of Bulletin release. The more interesting Bulletins this month address RCE and EoP vulnerabilities in Internet Explorer, Windows components, and yet again Exchange/OWA components licensed from Oracle. Also included in this month's release are fixes for RPC, kernel drivers, Active Directory, and the networking stack.

MS13-059 is the priority update to roll out across Windows clients, as it fixes nine critical memory corruption vulnerabilities (that look like use-after-free to me) in IE6, IE7, IE8, IE9, IE10 and even IE11 preview on Windows 8.1 preview, along with XSS due to flawed Kanji font handling and flawed code in the "Windows Integrity Mechanism", which is used for sandboxing apps like Internet Explorer, Adobe Reader and Google Chrome. On Windows server, the maximum severity is "Moderate" and doesn't effect "Server Core" installations at all. Admins need to refer to the severity ratings and maximum impact table to prioritize server patch deployments, but those that need to prioritize patch deployments probably shouldn't surf the web from these types of systems anyway.

MS13-060 corrects code in the Unicode Scripts Processor implementing OpenType font handling, a format developed by Microsoft and Adobe over the past decade built on top of the TrueType format, in USB10.dll. This dll is used by Windows and all sorts of third party applications to handle right-to-left scripts like Arabic and Hebrew, and other complex fonts like Indian and Thai scripts too. The vulnerability is a user mode vulnerability that effects only Windows XP SP 2 and 3 (64 bit too) and Windows 2003 versions. These types of systems continue to be widely deployed, especially in government and critical infrastructure systems around the world. Exploits may be delivered via spearphish, as in the Duqu incident, or via a web page for a browser like Internet Explorer, as in Duqu copycat malcode like the Blackhole exploit pack that continues to be widely distributed and highly active.

Another interesting update includes MS13-061 that patches code in third party components built by Oracle and licensed by Microsoft for Outlook Web Access on Exchange Server 2007, 2010, and 2013. Applying the patch will not require a system reboot, but it will restart related Exchange services. The interesting thing about this critical set of issues is that they enable exploitation of the WebReady Document Viewing and Data Loss Prevention features on OWA for code execution not on the client system, but on the server itself with LocalService credentials. So a client system browsing code sent to their email account can remotely execute code on the server in the service's context, which is very problematic.

Please review the set and update ASAP. While most of the vulnerabilities this month were privately reported, these present high risk opportunities and the Exchange issues and exploitation are publicly known.