Sniffers

Written by David M. Stone, University Laboratory High School, Urbana, IL

"Sniffer" is a generic term for computer programs which allow individuals to gather information regarding the status of components of a network system. In terms of computer crime, illegal sniffers are computer programs which search individual packets of information as they pass through various packet switching networks such as school servers or the Internet (Fighting Computer Crime: A New Framework for Protecting Information,1998). Written by computer hackers, illegal sniffers covertly capture information about an individual's computer or log user submitted information.

The structure of the Internet requires information to flow from computer node to computer node in its journey to its final destination. Illegal sniffers can be located at any of those nodes, stationed as phantom (invisible) nodes connected to a network, or act as Trojan horses within legitimate software. Information detectable by illegal sniffers can be used to remotely operate another's computer (or its associated server) for illicit purposes, steal passwords for access to privileged information or steal confidential information, such as credit card numbers submitted for online purchases.

Issues involving illegal sniffers are virtually nonexistent. Each of these different types of code provide no benefit whatsoever, and are clearly the efforts of individuals (malicious hackers) whose primary interest is gaining access privileges, impersonation or illegal economic gain.

Currently it appears that the best way to minimize sniffer interaction is by use of current high quality encryption software, which scrambles information so it cannont be translated by the sniffer. PGP (Pretty Good Protection) is an excellent encryption program to consider. Individuals desiring more information about PGP may want to consider reading "PGP : Pretty Good Privacy" (1995) by Simson Garfinkel. It is likely that hackers will constantly be upgrading the capabilities of their sniffers, requiring school and businesses to regularly upgrade encryption software.

Introduction to Encryption (http://www.symantec.com/avcenter/security/encryption/encryption.html)
A good, very concise overview of encryption. Produced by Symantec, top producer of security software.

Digital Key Security (http://cc.weber.edu/~itfm/hottopic/DIGITALK/digitalk2.htm)
Don't let the title scare you - this is an exceptionally well written web document which explains how encryption works. This site has a number of excellent links pertaining to each area discussed.

Progress Towards Strong Encryption (http://www.icsa.net/library/research/b.shtml)
An excellent introduction to recent encryption development technologies, best suited for intermediate to advanced users with some background in encryption.

PGP and What It Does (http://www.arc.unm.edu/~drosoff/pgp/pgp.html)
An outstanding introduction to encryption and the software program PGP.

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Developed 3/15/99. Last modified 5/9/99.