Although it has been a widely held belief among companies that insiders are responsible for most data breaches, a new study released June 11 claims 73 percent of breaches result from external sources versus 18 percent from insider threats.

Skewering some basic corporate security tenets, the study by Verizon Business also contends <A HREF="http://www.eweek.com/c/a/Security/Your-Data-Breach-Was-Probably-Avoidable/?kc=EWKNLNAVFEA1">nearly 9 in 10 data breaches could have been prevented</A> with reasonable security measures in place. The study covered four years and more than 500 investigations involving 230 million records.

Moreover, the study claims, most breaches resulted from a combination of events rather than a single action with 62 percent attributed to "significant internal errors" that either directly or indirectly contributed to a breach. For breaches that were deliberate, 59 percent were the result of hacking and intrusions.