Supposedly, the CISCO 500 Series PIX firewalls may have a flaw. The potential flaw is with the SIP protocol. By sending a certain packet to the PIX, hackers would be able to gain free reins to the UDP protocol to send any messages to the Internal network using UDP. For the full article, visit http://www.networkingpipeline.com/192201308?cid=rssfeed_pl_ntp