alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE UsefulTyphon CnC Activity M1";
flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:"/image?i="; fast_pattern;
content:"&u="; distance:0;
content:"&p="; distance:0;
pcre:"/&u=[a-f0-9]{16}&p=/";
http.header_names;
content:!"Accept";
content:!"Referer";
reference:md5,768c84100d6e3181a26fa50261129287;
classtype:command-and-control;
sid:2036502; rev:2;
metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_10_06, deployment Perimeter, malware_family Kimsuky, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_06;
)