Up until 2003 the Federal Bureau of Investigation (FBI) employed the custom-built the “Carnivore” system that took the guess-work out of monitoring electronic/network communications (i.e. e-mail), along with browsing activities, and other data sent across an internet connection.
This tool, far more sophisticated than your typical packet sniffers (though this is still reason enough to consider encrypting your electronic communications), allowed government agents to extract messages sent over a network while targeting and filtering specific
Carnivore became obsolete when, in 2003, it was replaced with even more sophisticated software that was more precise in deciphering communications and information that could *legally* by intercepted by law enforcement agencies (in accordance to Federal legislation).
While obsolete now (for intelligence gathering information at the level needed by the US government), the Carnivore System was an interesting experiment in how relatively easy (and unsafe) e-mail, and the internet in general, really is.
Using “sniffing” technology, the Carnivore system is installed at an Internet service provider (ISP) to keep court-ordered tabs on a suspect’s e-mail and instant messages. Prior to its becoming obsolete in 2003, it was confirmed to have been used in more than 150 criminal investigations.
Unlike some of the more emerging online-tapping systems, Carnivore had to “physically” be connected to a network in order to conduct surveillance. By connecting to the ISP, the system would then collect e-mails, websites visited, instant messages and all other forms of network activity. From here the aggragated data would be sent through a filter that would weed out information that could not be held up by a Court-ordered mandate allowing for the surveillance of electronic communications in the first place.
After being filtered – the information would then be stored on a removable disk and physically picked up by an FBI agent.
And while Carnivore is no longer the online-tapping system of the FBI anymore, it does give cause for concern about the ways in which anybody should take an active interest in ensuring their information security through a variety of means, ranging from rather simple to the much-more complicated.
On a final note – nearly all information-security experts recommend AGAINST purchasing proprietary security programs. Most so-called security companies, like MacAfee, have no qualms about leaving “back-doors” open for government Trojans. Your best bet is to stick with Open Source, such as the GNU Privacy Guard or even Mozilla’s Thunderbird e-mail client, which includes an easily-installed encryption extension known as “Enigma.”