alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING SUSPICIOUS Possible automated connectivity check (www.bing.com)"; flow:established,to_server; urilen:1; http.method; content:"GET"; http.host; content:"www.bing.com"; fast_pattern; http.header_names; to_lowercase; content:!"|0d 0a|user-agent|0d 0a|"; content:!"|0d 0a|content"; content:!"|0d 0a|accept"; content:!"|0d 0a|referer|0d 0a|"; threshold:type limit, count 1, seconds 300, track by_src; classtype:bad-unknown; sid:2018432; rev:4; metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2014_04_30, deployment Perimeter, performance_impact Moderate, confidence Medium, signature_severity Major, tag Web_Client_Attacks, updated_at 2024_04_30, reviewed_at 2024_03_06;)