alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected Chinese Based APT Malware Retrieving File (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/v1/disk/resources/download?path="; startswith; content:"/a.psd"; endswith; fast_pattern; http.host; content:"cloud-api.yandex.net"; bsize:20; http.header_names; content:"|0d 0a|Host|0d 0a|Accept|0d 0a|Authorization|0d 0a 0d 0a|"; bsize:33; reference:md5,0c4540f659d3942a28f158bce7be1143; reference:url,www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/apt31-cloud-attacks/; classtype:trojan-activity; sid:2038751; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_09_07, deployment Perimeter, deployment SSLDecrypt, malware_family TontoTeam, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_09_07;)