alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Base64 Encoded XML Declaration Within PNG File"; flow:established,to_client; http.response_body; content:"|89 50|"; startswith; content:"|49 48 44 52|"; distance:0; content:"|49 45 4E 44|"; distance:0; content:"PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0idXRmLTgiPz4"; distance:0; fast_pattern; threshold:type limit,count 1,seconds 300,track by_src; classtype:trojan-activity; sid:2072360; rev:1; metadata:affected_product Windows_Client, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_10_05, deployment Perimeter, deployment SSLDecrypt, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2026_10_05, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1189, mitre_technique_name Drive_by_Compromise; target:dest_ip;)