This is quite a funny exploit. Snort has problems handling ICMP "ECHO" and "ECHO-REPLY" packets that are under 5 bytes in side. If received the program will core dump. The exploit was discovered by ISS X-Force. Article here.
Who ever thought '$ ping -c 1 -s 1 <ip-address>' could be so much fun!
Please read http://www.snort.org/article.html?id=80