alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Bit.do Shortened Link Request (set)"; flow:established,to_server; flowbits:set,ET.bit.do.shortener; http.method; content:"GET"; http.header; content:"Host|3a 20|bit.do|0d 0a|Connection|3a 20|Keep-Alive|0d 0a|"; depth:38; fast_pattern; http.header_names; content:"|0d 0a|Host|0d 0a|Connection|0d 0a 0d 0a|"; depth:22; isdataat:!1,relative; classtype:misc-activity; sid:2029549; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_02_28, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_02_28;)