alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MirrorBlast CnC Activity M2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"=bmFtZT"; fast_pattern; pcre:"/(?:JmJ1aWxkP|YnVpbGQ9|ZidWlsZD)/R"; http.user_agent; content:"REBOL"; startswith; reference:url,twitter.com/ffforward/status/1441137165329649664; reference:md5,6b59a4657eb90d92590f5a183d9d1e77; classtype:command-and-control; sid:2034022; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_09_24, deployment Perimeter, malware_family MirrorBlast, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_09_24;)