Presumably due to firewall settings, I was not notified of Update 12 on only some servers on the DMZ, released on 11/12/13, via the ColdFusion administrator's handy "An Update For ColdFusion!" icon on my servers located on the DMZ. It was visible, however, on my intranet and development servers. This emphasizes the need for each developer to be notified of releases by more reliable means, such as following @ColdFusion on twitter or subscribing to the ColdFusion blog.
Since I'm running five ColdFusion servers, I downloaded the hotfix_012.jar file once and copied it to each server. I had to disable some security protocols in order to run the update. Once I did that, I visited the command prompt, and typed this in:
x:\my_path\to_the\cf_admin\jre\bin\java -jar y:\my\path\to_the_jar_file\hotfix_012.jar
This opens up the ColdFusion wizard, which took care of the rest of the installation. Very little downtime resulted from this quick update. Just ColdFusion's automatic service restart.
While the easiest way to install these updates would be if the ColdFusion Administrator's Download and Install worked for me, but it never has. This could be due to firewall settings, however.
The most difficult part of this install is typing into the command prompt with fat fingers, ensuring all security measures are temporarily disabled, and making sure the .jar file you download is placed in a folder that is accessible (read: not restricted by additional security measures).