alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Tech Support Phone Scam Landing M1 Jan 20 2017"; flow:established,to_client; http.stat_code; content:"401"; http.response_header; header_lowercase; content:"www-authenticate|3a 20|Basic|20|realm|3d 22|"; startswith; nocase; content:"warning|3a|"; distance:0; fast_pattern; content:"Call Microsoft"; nocase; classtype:social-engineering; sid:2023751; rev:5; 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 2024_04_28;)