Best Network Security Scanners

What are scanners?

Scanners, the subject of this post, are "neutral" network applications. this means that they can help both a hacker and an administrator. Their task is to collect information about network devices. As it turns out, this information can be quite varied. We are able to discover which software is used in the system, to check how long it has been running, and to find out about the available ports. Of course the scanners are written in such a way that their activity won't leave unwanted footprints on the target machine. It happens often that scanning is performed using undocumented protocols, the monitoring of which is usually ignored.

The advantages this presents may seem to be useful only to a hacker, but they are also important to an administrator. They allow us to make appropriate changes to the settings and improve the system security level.

There are three popular scanners, Nmap, Nessus, and Nikto. Each of these applications provides different functions, and they complement each other perfectly.

NMAP

 

Nmap (Network Mapper) is a security scanner originally written by Gordon Lyon (also known by his pseudonym Fyodor Vaskovich) used to discover hosts and services on a computer network, thus creating a "map" of the network. To accomplish its goal, Nmap sends specially crafted packets to the target host and then analyzes the responses. Unlike many simple port scanners that just send packets at some predefined constant rate, nmap accounts for the network conditions (latency fluctuations, network congestion, the target interference with the scan) during the run. Also, owing to the large and active user community providing feedback on its features and contributing back, nmap has succeeded to extend its discovery capabilities beyond basic host being up/down or port being open/closed to being able to determine operating system of the target, names and versions of the listening services, estimate uptime, the type of device, presence of the firewall. [from Wikipedia]

Nmap runs on Linux, Microsoft Windows, Solaris, HP-UX and BSD variants (including Mac OS X), and also on AmigaOS and SGI IRIX. Linux is the most popular nmap platform with Windows following it closely.

Nessus

 

Nessus is an application that is worth to discuss about. This program is similar in funcionality to nmap, but it distinguishers itself by an extended error detabase, updated every day, that is very useful for the user. In addition, Nessus is easy to keep up to date, using a plugin system for this purpose. The plugins are created with a special NASL script language. Information about the application can be obtained on the homepage of the project: http://www.nessus.org/

Nikto

Nikto performs comprehensive tests against web servers for multiple items, including over 6100 potentially dangerous files/CGIs, versions on over 950 servers, and version specific problems on over 260 servers.

Regards: Anshuman kak a Script kiddie