Interesting article on TechNet:
Law #1:
If a bad guy can persuade you to run his program on your computer, it’s not solely your computer anymore.
Law #2:
If a bad guy can alter the operating system on your computer, it’s not your computer anymore.
Law #3:
If a bad guy has unrestricted physical access to your computer, it’s not your computer anymore.
Law #4:
If you allow a bad guy to run active content in your website, it’s not your website any more.
Law #5:
Weak passwords trump strong security.
Law #6:
A computer is only as secure as the administrator is trustworthy.
Law #7:
Encrypted data is only as secure as its decryption key.
Law #8:
An out-of-date antimalware scanner is only marginally better than no scanner at all.
Law #9:
Absolute anonymity isn’t practically achievable, online or offline.
Law #10:
Technology is not a panacea.