alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET MALWARE Unattributed WebShell Access - File Upload"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"exec_code=put"; fast_pattern; content:"delimiter="; content:"dst="; reference:url,thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/; classtype:attempted-admin; sid:2034500; rev:1; metadata:created_at 2021_11_18, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_18;)