Authenticity and the November 2013 Security Updates

If you haven’t had a chance to see the movie Gravity, I highly recommend you take the time to check it out. The plot moves a bit slowly at times, but director Alfonso Cuaron’s work portrayal of zero gravity is worth the ticket price alone. Add in stellar acting and you end up with an epic movie that really makes you miss the shuttle program. Still, the movie has its detractors. Specifically, astrophysicist and geek icon Neil deGrasse Tyson has been critical about the movie’s authenticity. To deGrasse Tyson, a lack of authenticity disrupts the movie-going experience.

Similarly, a lack of authenticity can disrupt your computing experience, which leads me to a couple of interesting items in this month’s release. Two advisories this month deal with authenticity by focusing on certificates and cryptography. The first is Security Advisory 286725, which disables the use of the RC4 stream cipher. As computing power increases, cryptographic attacks that were once only theoretical become practical - this is the case with RC4, which was originally designed in 1987. That’s the same year The Simpsons first appeared as shorts on The Tracy Ullman Show. Computing has changed somewhat in that time.

We’ve already taken this step in Windows 8.1 and Internet Explorer 11, and now we’re providing an update to disable its use in other operating systems as well. Rather than automatically disable the cipher, the update provides a registry key that allows developers to eliminate RC4 as an available cipher in their applications. The SRD blog provides a deep dive into RC4 and the implications of disabling it.

Security Advisory 2880823 also impacts cryptography and authenticity but addresses SHA1. We aren’t going to surprise the world by saying we’re turning off support for SHA1 today, but we are announcing a new policy for Certificate Authorities (CAs) that deprecates the use of the SHA1 algorithm in SSL and code signing certificates in favor of the SHA2 algorithm. After January 2016, only SHA2 certificates can be issued. The good folks over on the PKI blog go into more detail about the change.

We have an update regarding a cryptographic function as well, MS13-095 addresses an issue in Digital Signatures that could cause a web service to stop responding if it receives a specially crafted X.509 certificate. Since these certificates are used to ensure authenticity, having the web service go down during negotiation is suboptimal.

Of course, another way to help ensure authenticity throughout your computing experience is to use EMET. An updated version of the program is available today. Of the many improvements, there is an update to the default settings that includes two new application protection profiles for applications. There’s also an update for the Certificate Trust profile that offers more applications protection. Full details about this release can be found on the SRD blog. It may not patch any holes, but it can make it harder to reach any issue that may exist on a system and, if your family is like mine, it will significantly reduce calls from relatives looking for tech support.

Of course it takes more than just authenticity to make a secure computing experience, which leads us to the other updates for November. Today, we released eight bulletins, three Critical and five Important, addressing 19 unique CVEs in Microsoft Windows, Internet Explorer, and Office. For those who need to prioritize their deployment planning we recommend focusing on MS13-090, MS13-088, and MS13-089.

Our Bulletin Deployment Priority graph provides an overview of this month’s priority releases (click to enlarge).

MS13-090 | Cumulative Security Update of Active X Kill Bits This update addresses a remote code execution issue in an ActiveX control by providing a kill bit for associated ActiveX controls. We are aware of limited attacks that exploit this issue. The code execution occurs at the level of the logged on user, so non-admin users would face less of an impact. The remote code execution vulnerability with higher severity rating be fixed in today’s release and we advise customers to prioritize the deployment of MS13-090 for their monthly release. As usual, customer with Automatic Updates enabled will not need to take any action to receive the update. Additional information about this vulnerability is available on the Security Research & Defense blog.

MS13-088 | Cumulative Update for Internet Explorer This security update resolves ten privately reported vulnerabilities in Internet Explorer. The most severe vulnerabilities could allow remote code execution if a user views a specially crafted webpage using Internet Explorer. An attacker who successfully exploited the most severe of these vulnerabilities could gain the same user rights as the current user.

MS13-089 | Vulnerability in Windows Graphics Device Interface Could Allow Remote Code Execution This update addresses one privately reported vulnerability in Microsoft Windows. The vulnerability could allow remote code execution if a user views or opens a specially crafted Windows Write file in WordPad. An attacker who successfully exploited this vulnerability could gain the same user rights as the current user.

Last but not least, we are also providing an update for users of DirectAccess (DA) through Security Advisory 2862152. This security feature bypass issue would require a man-in-the-middle attacker to be successful, but if someone can snoop on your DA connection, it’s possible they could impersonate a legitimate DA server in order to establish connections with legitimate DA clients. The attacker-controlled system could then intercept the target user’s network traffic and potentially determine the encrypted domain credentials. This update, along with the new configuration guidelines available in KB2862152, helps ensure the authenticity of DA connections.

Watch the bulletin overview video below for a brief summary of today’s releases.

https://www.youtube.com/watch?v=gwNAfmqhBCE

Our risk and impact graph shows an aggregate view of this month’s Security and Exploitability Index (click to enlarge).

For more information about this month’s security updates, including the detailed view of the Exploit Index broken down by CVE, visit the Microsoft Bulletin Summary Webpage.

Jonathan Ness and I will host the monthly bulletin webcast, scheduled for Wednesday, November 13, 2013, at 11 a.m. PST. I invite you to register here and tune in to learn more about this month’s security bulletins and advisories. We’ll provide authentic answers to your update deployment questions, but no zero gravity effects will be employed.

For all the latest information, you can also follow the MSRC team on Twitter at @MSFTSecResponse.

I look forward to hearing your questions in the webcast tomorrow.

Thanks,

Dustin Childs
Group Manager, Response Communications
Microsoft Trustworthy Computing