We have changed the way that we classify security updates that are related to Microsoft security advisories and bulletins. This change will help enterprise administrators clearly identify updates that have security implications.
We can correctly classify security advisory updates that do not relate to a vulnerability in Microsoft code but do have security implications.
For these kinds of security issues, customers can expect to see the "MSRC Severity" rating set to "Unassigned." Also, customers should be aware that we will not change the classification of bulletins and advisories that were released before May 2013.
Previously, security-related content that was released together with a security advisory was classified as a nonsecurity update, usually by using the "Critical" update classification. Going forward, such content will be classified as a "Security update" with the "MSRC Severity" rating as "Unassigned." This can be a source of confusion for enterprise administrators who know about the security advisory but do not see a security update in their Microsoft Windows Server Update Services (WSUS) server consoles. This change will enable enterprise administrators to more quickly identify updates that affect security and to more effectively associate security content that relates to security advisories.
Microsoft Security Bulletins may also be classified in this manner. For example, during the investigation of a security vulnerability, we may find a scenario in which the exploitation of the vulnerability is confirmed to affect one version of one product but is not exploitable on another product that uses similar code. In this scenario, we will likely be proactive and comprehensively address both products. For such issues (that is, issues in which we release an update as a defense in depth measure), we may also classify the packages by using the "MSRC Severity" rating of "Unassigned."