alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Office Doc Retrieving Shortened URL (bit .do)"; flow:established,to_server; http.method; content:"GET"; http.user_agent; content:"|3b 20|ms-office|3b 20|"; http.host; content:"bit.do"; bsize:6; fast_pattern; reference:md5,04a303e67b4a2f9f7bb532779aef2c72; classtype:bad-unknown; sid:2033133; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_06_10, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_06_10;)