In order to bring up nessus using the Web User Interface, you will first need to click on the Nessus link which appears in the Networking table of the WUI. Look at the row labeled Scan as shown in the following:

Figure 2.1. Selecting nessus

Before running a nessus scan on the network, you'll need to start the nessus daemon. The WUI provides two options for starting the daemon. If you select the Start Nessus with Local Plugins, then the scans will include the information available at the time the Network Security Toolkit was built. If you press the Start Nessus with Latest Plugins, the latest set of scanning rules will be downloaded from the nessus web site prior to starting the nessus daemon (don't use this option if your Network Security Toolkit probe does not have access to the Internet).

Make a decision as to whether you want the Network Security Toolkit to download the latest nessus rules or not and then press one of the two buttons shown below:

Figure 2.2. Starting nessus daemon

Unfortunately, it takes a bit of time to start the nessus daemon. As a result, the Network Security Toolkit probe will inform you that it is still in the progress of bringing up the nessus daemon. You will need to be patient and periodically hit your web browser's refresh button, or click on the here link shown below until the Network Security Toolkit probe indicates that its ready to run a nessus scan:

Figure 2.3. Waiting for nessus daemon to start

Eventually, you'll find that after pressing the refresh button enough times, the nessus daemon will eventually be found to be running. At this point, you'll be presented with a very simple interface to the nessus daemon. By default, it should already have the IP address of your system filled in. If you only wanted to scan your system, you could simply press the Start Scan button at this point in time.

Figure 2.4. nessus ready to scan

Instead of scanning just my laptop. In this example, I've decided to tell nessus to scan the systems ranging from 192.168.0.5 to 192.168.0.12. The following shows how I specified this range of IP addresses and the Start Scan button that needs to be pressed to begin the scan.

Figure 2.5. nessus ready to scan

After pressing the Start Scan button, the Network Security Toolkit probe comes back indicating what system(s) are being scanned and that it will take a long time. Once again, I will need to be patient and wait for nessus to complete its work. While waiting, I can click on the refresh link to check on the progress.

Figure 2.6. nessus Scan Starting

My last press of the refresh button tells me that nessus is still in the progress of running its scan. These scans are very thorough and can take a LONG time (think lunch). From the snippet shown below, I see that its running tests 107-110 on 192.168.0.12, tests 313-316 on 192.168.0.5, and tests 321-322 on system 192.168.0.11. I also see that there are 1727 tests total that will be run against all of the systems.

Figure 2.7. nessus Scan Progress

Finally, a press of the refresh button has yielded something other than a message telling me that the scan is still in progress. I finally have the results of my nessus scan available! With great excitement, I click on the Top link.

Figure 2.8. nessus Scan Complete

The Nessus Report tells me that nessus found 14 security holes!

Figure 2.9. Nessus Report

I wasn't too pleased to hear that nessus detected 14 security holes on my network. I scrolled to the bottom of the page to find that system 192.168.0.12 had was responsible for 10 of the security holes. I then click on the link for system 192.168.0.12 to see what security issues were found:

Figure 2.10. Nessus Results, by host

After clicking on the link provided by nessus, I immediately know why there were so many security holes found by nessus. System, 192.168.0.12 is my Lexmark 412N laser printer. I forgot to turn it off prior to running the scan! If you'll remember back to the start of this section, I clearly stated that it was a bad idea to let nessus scan your networked printers. Sure enough, I forgot to turn mine off and wasted another 15 sheets of paper. After smacking myself on the forehead, I decided to see why nessus thought it found a security hole at port 80.

Figure 2.11. Nessus Finds Hole On Printer Port 80

It appears that nessus was able to aquire the source code for some of the CGI scripts used by my Lexmark printer. Currently, I don't worry too much about the security of this network printer (I rely on a firewall and knowing the users which have access to it). However, if I were to be paranoid, I might consider searching for patches, or attaching the printer to a networked Linux box instead of putting it directly on the LAN.

Figure 2.12. Nessus Reports CGI Source Code Found