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;)