alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE APT29/WellMess CnC Activity"; flow:established,to_server; content:"+++|0d 0a|"; fast_pattern; urilen:1; http.method; content:"POST"; http.cookie; content:"+++"; endswith; http.request_body; pcre:"/^(?:[\x3a\x2c\x2e]?[A-Za-z0-9]{1,8}[\x3a\x2c\x2e]?[\x3a\x2c\x2e]?\s*){50,}$/si"; http.header_names; content:!"Referer"; reference:md5,861879f402fe3080ab058c0c88536be4; reference:url,ncsc.gov.uk/files/Advisory-APT29-targets-COVID-19-vaccine-development.pdf; classtype:trojan-activity; sid:2030534; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Linux, attack_target Client_Endpoint, created_at 2020_07_16, deployment Perimeter, malware_family WellMess, confidence High, signature_severity Major, updated_at 2020_09_16;)