alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected Gamaredon APT Related Maldoc Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"_"; content:"/office.txt"; within:26; endswith; fast_pattern; http.header_names; content:!"Referer"; reference:md5,97d3d3fe312514f33a44dcd9d5887b54; reference:url,unit42.paloaltonetworks.com/gamaredon-primitive-bear-ukraine-update-2021/; classtype:trojan-activity; sid:2035218; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_02_18, deployment Perimeter, malware_family Gamaredon, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_02_18;)