alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected Gamaredon Related Maldoc Activity M2"; flow:established,to_server; http.method; content:"OPTIONS"; http.uri; content:"/USER-"; startswith; fast_pattern; http.user_agent; content:"Microsoft Office"; startswith; http.header_names; content:"|0d 0a|X-MSGETWEBURL|0d 0a|X-IDCRL_ACCEPTED|0d 0a|"; reference:md5,fa1039ec7779e5c1431fa072e7aa85aa; classtype:trojan-activity; sid:2045808; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_05_20, deployment Perimeter, malware_family Gamaredon, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_05_20;)