What are today’s most significant threats to network security?
Phishing is pretty common. It’s a type of social engineering. Social engineering gets people to do what you want them to, thereby allowing an attack to proceed regardless of security.
Poor passwords –
Not having two-factor authentication on wireless access points leaves them more vulnerable to attack. While not so common, I think it will become more common once more criminals figure out how easy it can be to exploit a wireless access point regardless of the password used.