alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET WEB_CLIENT Tech Support Phone Scam Landing M1 Jun 29 2016"; flow:established,to_client; http.stat_code; content:"401"; http.response_header; header_lowercase; content:"www-authenticate|3a 20|Basic|20|realm|3d 22|"; nocase; content:"has been blocked"; nocase; distance:0; fast_pattern; classtype:social-engineering; sid:2022925; rev:7; metadata:attack_target Client_Endpoint, created_at 2016_06_29, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Phishing, updated_at 2024_04_28;)