How Vulnerable Is The Emergency Alert System?

I'm sure by now everyone has heard about the Emergency Alert System "Zombie Attack" incident. IOActive even released a security advisory about the vulnerabilities with DASDEC Emergency Alert System digital alert systems. However, the incident raises further concerns, such as "who in their right mind hooked up the Emergency Alert System to the Internet in the first place?"

If someone wanted to hack the Emergency Alert System, first they would need to know what hardware/software is out there. (Un)fortunately the FCC has already done part of this research and published a vendor list.