Arraya Insights | November 21, 2014
Heads up: Microsoft has just released a critical update needed to patch an elevation of privilege vulnerability lurking in Kerberos KDC.
This flaw – known as Kerberos Checksum Vulnerability – could give an attacker the ability to increase the privileges of a standard user account up to the level of domain administrator. From there, the attacker might use those elevated privileges to compromise any computer in that domain – including the domain controllers.
The security update needed to correct the flaw has been rated critical for all supported editions of Windows Server 2003, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, and Windows Server 2012 R2. The update is also being offered on a defense-in-depth basis for all supported editions of Windows Vista, Windows 7, Windows 8, and Windows 8.1.
This vulnerability occurs when Microsoft Kerberos KDC implementations don’t accurately authenticate signatures. This failure could let an attacker forge a Kerberos service ticket and claim that he or she is actually a domain administrator. When Kerberos processes the forged request, the attacker would then essentially have free access to the network. The update seals up the vulnerability by correcting the signature verification issues.
In order to exploit this flaw, an attacker must have valid domain credentials. In addition, standard user accounts credentials are needed to break into a system. The vulnerability can’t be exploited using account credentials that are local access only.
Microsoft discovered the vulnerability through a coordinated vulnerability disclosure. So far, there have been limited, target efforts by attackers to take advantage of the Kerberos flaw. However, none of the attacks have affected Windows Server 2012 or Windows Server 2012 R2 environments.
If your team has enabled automatic updates, they should still take the time to make sure the patch has been fully installed. Even though Windows will automatically download and begin the installation, the patch won’t actually take effect until the domain controllers have been rebooted, so the risk will remain. If automatic updates haven’t been enabled, administrators will need to check for the necessary updates and then install them manually.
These are the types of situations where having a partner like Arraya Solutions can certainly come in handy. Arraya’s Manage 365+ can monitor your business environment to ensure it’s healthy, secure and running at the highest possible level. It can also take managing service requests, scheduled maintenance and updates off of your IT team’s plate, freeing your team up to focus on more pressing projects.
To find out more about how Arraya can help, visit www.ArrayaSolutions.com or reach out to your Arraya sales rep today.