alert tcp $HOME_NET any -> $EXTERNAL_NET 80 (msg:"ET HUNTING SUSPICIOUS Possible automated connectivity check (www.bing.com)"; flow:established,to_server; dsize:38; content:"GET / HTTP/1."; content:"|0d 0a|Host|3a 20|www.bing.com|0d 0a 0d 0a|"; distance:1; within:24; fast_pattern; threshold:type limit, count 1, seconds 300, track by_src; classtype:bad-unknown; sid:2018432; rev:3; 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;)