Schneier on Security: The Human Side of Security:

A funny -- and all too true -- addition to the SANS Top 20:

H1. Humans

H1.1 Description:

The species Homo sapiens supports a wide range of intellectual capabilities such as speech, emotion, rational thinking etc. Many of these components are enabled by default - though to differing degrees of success. These components are implemented by the cerebral cortex, and are under the control of the identity engine which runs as me.exe. Vulnerabilities in these components are the most common avenues for exploitation.

(Via Schneier on Security.)