alert http $HOME_NET any -> $EXTERNAL_NET any (
msg:"ET MALWARE Unknown Rootkit Download Activity (GET)";
flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:"/api/safe/"; startswith;
content:"?appid="; distance:0;
content:"&m="; distance:0;
content:"&nonce_str="; distance:0;
content:"&time_stamp="; distance:0;
content:"&sign="; distance:0;
http.user_agent;
content:"Http-connect"; bsize:12; fast_pattern;
http.header_names;
content:!"Referer";
content:!"Accept";
reference:md5,3f295401fa59a32ff7a11551551ec607;
reference:url,twitter.com/starsSk87264403/status/1422543872853426198;
classtype:trojan-activity;
sid:2033647; rev:1;
metadata:attack_target Client_Endpoint, created_at 2021_08_03, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_03;
)