alert http [$HOME_NET,$SMTP_SERVERS] any -> any any (msg:"ET MALWARE JS SpyPress C2 Beacon"; flow:established,to_server; http.request_line; content:"GET /?cl="; startswith; pcre:"/^[A-Za-z0-9\x25\x2b\x2f\x3b]+\x20/R"; reference:url,www.proofpoint.com/us/blog/threat-insight/ta458-roundpress-exploits; classtype:trojan-activity; sid:2071250; rev:1; metadata:attack_target Client_Endpoint, created_at 2026_07_21, deployment Perimeter, malware_family SpyPress, confidence High, signature_severity Major, tag c2, updated_at 2026_07_21, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel; target:src_ip;)