alert tcp any any -> $HOME_NET !$HTTP_PORTS (msg:"ET RETIRED Malformed HeartBeat Request"; flow:established,to_server; content:"|18 03|"; depth:2; byte_test:1,<,4,2; content:"|01|"; offset:5; depth:1; byte_extract:2,3,record_len; byte_test:2,>,2,3; byte_test:2,>,record_len,6; threshold:type limit,track by_src,count 1,seconds 120; flowbits:set,ET.MalformedTLSHB; reference:cve,2014-0160; reference:url,blog.inliniac.net/2014/04/08/detecting-openssl-heartbleed-with-suricata/; reference:url,heartbleed.com/; reference:url,blog.fox-it.com/2014/04/08/openssl-heartbleed-bug-live-blog/; classtype:bad-unknown; sid:2018372; rev:4; metadata:created_at 2014_04_08, cve CVE_2014_0160, former_category EXPLOIT, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_04_17;)