alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected APT37 Related Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/install.bak/"; startswith; fast_pattern; pcre:"/\/[0-9]{2}\.html$/R"; http.user_agent; content:"Mozilla/4.0"; startswith; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; reference:md5,e89725778e52fa571a229cc6e65acd8d; reference:md5,9bf4576a1381c15c08060ca6cfd59949; reference:url,twitter.com/suyog41/status/1640662025247289345; classtype:trojan-activity; sid:2044834; rev:2; metadata:attack_target Client_Endpoint, created_at 2023_03_30, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_26; target:src_ip;)