Nikto is available in Ubuntu 10.10 multiverse, as well as in the latest Fedora.
Install it as usual:
sudo apt-get install nikto
yum install nikto
Now, update nikto to the latest scanning vulnerabilities by issuing:
sudo nikto -update
Then, run nikto -h host to do a basic scan on port 80. It will take several minutes to complete and give you a detailed analysis.
Here is a random example:
[root@fedora ~]# nikto -h example.com
– Nikto v2.1.1
+ Target IP: 192.168.1.1
+ Target Hostname: example.com
+ Target Port: 80
+ Start Time: 2010-11-07 20:34:32
+ Server: Apache
+ No CGI Directories found (use ‘-C all’ to force check all possible dirs)
+ Allowed HTTP Methods: GET, HEAD, POST, OPTIONS
+ 4059 items checked: 1 item(s) reported on remote host
+ End Time: 2010-11-07 20:37:53 (201 seconds)
+ 1 host(s) tested
Of course nikto can do much, much more, but this should hopefully get you started.
Warning! As with any scanning software, this will fill up logs with your actions. Here is an example apache log snip.