alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET EXPLOIT_KIT ZPHP Domain in TLS SNI (yappiexpress .com)"; flow:established,to_server; tls.sni; bsize:16; content:"yappiexpress.com"; fast_pattern; reference:url,www.proofpoint.com/us/blog/threat-insight/are-you-sure-your-browser-date-current-landscape-fake-browser-updates; reference:url,infosec.exchange/@monitorsg/112202024632866495; classtype:exploit-kit; sid:2051913; rev:3; metadata:affected_product Web_Browsers, attack_target Client_Endpoint, created_at 2024_04_03, deployment Perimeter, deprecation_reason Relevance, former_category RETIRED, performance_impact Low, confidence High, signature_severity Minor, tag Exploit_Kit, tag compromised_website, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_06_18, reviewed_at 2024_06_18;)