alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE Mespinoza Ransomware - Pre-Encryption File Exfil to CnC";
flow:established,to_server;
http.uri;
content:"/upload-"; startswith; fast_pattern;
content:"?token=";
pcre:"/^(?:[A-Z0-9+/]{4})*(?:[A-Z0-9+/]{2}==|[A-Z0-9+/]{3}=|[A-Z0-9+/]{4})/R";
content:"&id="; distance:0;
content:"&fullPath="; distance:0;
reference:url,unit42.paloaltonetworks.com/gasket-and-magicsocks-tools-install-mespinoza-ransomware/;
classtype:command-and-control;
sid:2033343; rev:1;
metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_07_15, deployment Perimeter, malware_family Mespinoza, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_15, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;
)