alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE Locky CnC checkin Nov 21";
flow:to_server,established;
http.method;
content:"POST";
http.uri;
pcre:"/^\/[^\x2e\x3f\x3d\x26]+\.[^\x2e\x2f\x3f\x3d\x26]+$/";
http.header;
content:"x-requested-with|3a 20|XMLHttpRequest|0d 0a|";
content:"www-form-urlencoded|0d 0a|";
http.referer;
pcre:"/^http\x3a\x2f\x2f[^\x2f]+\x2f$/";
http.request_body;
pcre:"/^(?:[A-Za-z]{1,10}=(?=[A-Za-z0-9_+\x2d\x2e%]*%[A-F0-9]{2}%[A-F0-9]{2}%[A-F0-9]{2})[A-Za-z0-9_+\x2d\x2e%]+&)+(?=[a-z]{0,9}[A-Z])(?=[A-Z]{0,9}[a-z])[A-Za-z]{1,10}=(?=[A-Za-z0-9_+\x2d\x2e%]*%[A-F0-9]{2}%[A-F0-9]{2}%[A-F0-9]{2})[A-Za-z0-9_+\x2d\x2e%]+\s*$/";
classtype:command-and-control;
sid:2023551; rev:4;
metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2016_11_21, deployment Perimeter, malware_family Locky, performance_impact Low, confidence High, signature_severity Major, updated_at 2020_12_11;
)