Five out of Six Firewalls Certified by Other Labs Let External Hackers In.
http://www.networkworld.com/news/2011/041211-hacker-exploit-firewalls.html
Hacker 'handshake' hole found in common firewalls
NSS Labs tested Cisco, Check Point, Fortinet, Juniper, the Palo Alto Networks, and SonicWall firewalls
Some of the most commonly-used firewalls are subject to a hacker exploit that lets an attacker trick a firewall and get into an internal network as a trusted IP connection.
Five of the six products allowed external attackers to bypass the firewall and become an internal 'trusted machine.'" The only firewall tested by NSS labs that didn't was the Check Point one.