No, it most probably is not. At least I did not add one. rkhunter sent me a warning about the old version of apache. I figured that Plesk would somehow keep Apache up-to-date.
How can I update apache 2.2.15 to a current 2.2.x version?
"yum update httpd"
gives me
"No Packages marked for Update"
The same question was asked long ago, but the thread is gone:
http://forum.parallels.com/showthread.php?298445-Updating-apache-from-2-2-15-to-2-2-26
This might also be...