Jesus. That's been out of support for well over 2 years. I can't imagine this is the only problem it has. I'm curious: what's keeping the organization from upgrading it?
07:26:20 up 3280 days, 16:23, 2 users, load average: 0.00, 0.00, 0.00
$ cat /etc/issue
Debian GNU/Linux 3.1 \n \l
Variety is the spice of life, and all that...
(ancient openssl never had tls heartbeat feature)
But Redhat actually still supports EL4 through their ELS program and releases patches for it until March 31, 2017
CentOS simply decided not to keep up with it anymore, cannot blame them.
You find a lot of that type in education/local government.