alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected DonotGroup Dropper Activity"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/@/"; startswith; content:"/tele.txt"; fast_pattern; http.host; content:"microsoft-updates.servehttp.com"; bsize:31; reference:md5,f23dd9acbf28f324b290b970fbc40b30; classtype:trojan-activity; sid:2033363; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_07_20, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_20;)