alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Tech Support Phone Scam Landing M1 Jan 20 2017"; flow:from_server,established; http.stat_code; content:"401"; http.header; content:"WWW-Authenticate|3a 20|Basic realm=|22|"; nocase; content:"Warning|3a|"; nocase; distance:0; fast_pattern; content:"Call Microsoft"; nocase; classtype:social-engineering; sid:2023751; rev:3; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2017_01_20, deployment Perimeter, confidence High, signature_severity Major, tag Phishing, updated_at 2020_08_03;)