alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Terse Request to note .youdao .com - Possible Download"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/yws/api/personal/file/"; content:"?method=download&shareKey="; distance:0; pcre:"/[a-f0-9]{32}$/UR"; http.host; content:"note.youdao.com"; fast_pattern; bsize:15; http.header_names; content:"|0d 0a|User-Agent|0d 0a|Host|0d 0a 0d 0a|"; bsize:22; content:!"Referer"; reference:url,twitter.com/malwrhunterteam/status/1509160261881667585; classtype:misc-activity; sid:2035681; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_03_30, deployment Perimeter, deployment SSLDecrypt, performance_impact Moderate, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_03_31, reviewed_at 2025_04_17;)