alert http $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"ET DELETED Possible OptionsBleed (CVE-2017-9798)"; flow:established,to_server; content:"OPTIONS"; http_method; flowbits:set,ET.2017-9798; threshold:type both, count 30, seconds 30, track by_src; classtype:misc-activity; sid:2024759; rev:6; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_09_19, cve 2017_9798, deployment Perimeter, performance_impact Moderate, signature_severity Major, updated_at 2019_07_26;)