Several weeks ago, a good friend of my family who is a lawyer for an application hosting company and I were speaking about network security and I brought up Nessus. "Can you scan one of our hosted sites?" he asked. A short while later, especially after asking the right sort of legal questions, we were looking at the results of a non-credentialed Nessus scan for a high traffic web site.
His web site didn't have any "application" content and hosted static HTML web pages. The only odd thing to note was an SSH server found on a very high port.
"Is that bad?" asked my friend.
"Well, it doesn't have any publicly known vulnerabilities." I said.
"So that's good, right?".
I told him I had two thoughts.
First, if the administrator thought to actually put the SSH server on a port other than 22, they might also want to take some extra steps and perhaps lock down SSH a bit tighter, or even mask it from generic access to the Internet. They may have been able to disabled some unneeded functionality of SSH, avoid using passwords or potentially use some sort of firewall or VPN so I couldn't connect to their SSH daemon.
Second, my friend should ask the administrator of that site if they noticed any unauthorized login attempts through SSH or from the other services. Nessus tries all sorts of things to the various services it probes and this activity generates logs in the form of failed login attempts and error messages. If there is any type of monitoring activity ongoing, it should alert on some part of the Nessus scan.
"I had heard them say that SSH was secure." he commented.
I then pulled up all the SSH vulnerabilties and patch audits that Nessus can check for and showed him. He was initially concerned that SSH wasn't secure, period. I had to spend a short bit of time explaining vulnerability life-cycles and how an undiscovered vulnerability can be latent in operating systems and applications right now.
These statements didn't provide much comfort.
On a lark, I showed him some Nessus scans of web sites that had many different types of vulnerabilities. This had the opposite effect I was intending in that he was somewhat comforted by the fact his web site was better off than others.
What I felt was really interesting about our conversation was that we never once mentioned things like CVSS or NSA Best Practice hardening guides. What he really wanted to know was if they were secure or not. Is there something someone on their staff was doing wrong or something else they could do better? Although not an IT or network security practitioner, as a lawyer, he was putting everything in terms of risk to the business which is a good thing.
