[CentOS] what percent of time are there unpatched exploits against default config?

[Stephen Harris]

On Sat, Dec 31, 2011 at 05:43:54AM -0800, Drew wrote:
> The argument I saw against PKI is that's it's no more secure then
> regular passwords because your certificates are password protected
> anyways and stored on external media so they can be stolen and used to
> access the system.

Typical security is based around three things:
  1. Something you know  (eg password)
  2. Something you have  (eg physical token, USB key, ssh private key)
  3. Something you are   (eg fingerprint)

Passwords are "1 factor"; it's just a password.  RSA SecurID tokens
are "2 factor"; you need the number on the token and the PIN.  The more
factors you have, typically the stronger the protection.  (Assuming proper
implementation, of course!)

In the same way, public key authentication is 2 factor (in the SSH
implementation, anyway) because you need the private key and the
passphrase to the key.  (historically, passphrases were longer than
8 character passwords but that's not so true on many systems, today)

Why is this more secure?  Because a gazillion people can brute force
attack a box protected by passwords, however only people who have
physical access to the token (#2) can attack my box.  By stealing the
token they've reduced my protection to single factor.  BUT, and this is
an important but, they _have to steal it first_.

SSH keys are weaker than RSA tokens because an SSH key can be duplicated
without the owners knowledge; if you steal my RSA key then I'll know!
But you still need to duplicate it, and that makes it stronger than
password auth.

-- 

rgds
Stephen