alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE PXJ Ransomware CnC Activity"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/do.php?token_value="; fast_pattern; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R"; http.header_names; content:!"Accept"; content:!"Referer"; reference:md5,142ed79d41f3e9551b6d2fa7bcfd1590; reference:url,securityintelligence.com/posts/pxj-ransomware-campaign-identified-by-x-force-iris/; classtype:command-and-control; sid:2029615; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_03_12, deployment Perimeter, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_03_12, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;)