alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Android Device Connectivity Check"; flow:established,to_server; urilen:13; http.method; content:"GET"; http.uri; content:"/generate_204"; fast_pattern; endswith; http.host; content:"connectivitycheck.gstatic.com"; http.accept_enc; content:"gzip"; depth:4; endswith; http.header_names; content:!"Cache"; content:!"Referer"; classtype:misc-activity; sid:2036220; rev:4; metadata:affected_product Android, attack_target Mobile_Client, created_at 2018_09_14, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Informational, tag Connectivity_Check, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_05_01;)