alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE DonotGroup Pult Downloader Activity (POST)"; flow:established,to_server; urilen:8<>25; http.method; content:"POST"; http.uri; content:!".php"; http.content_type; content:"application/x-www-form-urlencoded"; bsize:33; http.request_body; content:"batac="; startswith; fast_pattern; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R"; http.user_agent; content:!"Linux|3b|"; content:!"iPhone|3b|"; http.header_names; content:"|0d 0a|Content-Type|0d 0a|User-Agent|0d 0a|Host|0d 0a|Content-Length|0d 0a|Cache-Control|0d 0a 0d 0a|"; content:!"Referer"; reference:md5,765c01936caae2ba1b1b50ae1ed76cc0; classtype:trojan-activity; sid:2035534; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_03_18, deployment Perimeter, deployment SSLDecrypt, malware_family DonotGroup, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_03_18;)