Suricata

To test this, check out the git master and add these 2 rules:

alert tls any any -> any any (msg:"SURICATA TLS overflow heartbeat encountered, possible exploit attempt (heartbleed)"; flow:established; app-layer-event:tls.overflow_heartbeat_message; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; reference:cve,2014-0160; sid:2230012; rev:1;)
alert tls any any -> any any (msg:"SURICATA TLS invalid heartbeat encountered, possible exploit attempt (heartbleed)"; flow:established; app-layer-event:tls.invalid_heartbeat_message; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; reference:cve,2014-0160; sid:2230013; rev:1;)