alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Gamaredon Style MalDoc .dot Download on freedynamicdns .org"; flow:established,to_server; http.method; content:"HEAD"; http.uri; content:".dot"; endswith; pcre:"/\/[A-Za-z]{4,9}\.dot$/"; http.host; content:".freedynamicdns.org"; endswith; fast_pattern; reference:md5,2180fa8e767676a6802cf3d5d23ea6de; classtype:trojan-activity; sid:2030232; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_06_01, deployment Perimeter, confidence High, signature_severity Major, updated_at 2020_06_01;)