alert http1 $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Suspected REDCURL CnC Activity M1"; flow:established,to_server; http.method; content:"PROPFIND"; http.uri; content:".bat"; endswith; http.header_names; bsize:68; content:"|0d 0a|Connection|0d 0a|User-Agent|0d 0a|Depth|0d 0a|translate|0d 0a|Content-Length|0d 0a|Host|0d 0a|"; fast_pattern; content:!"Referer"; content:!"Accept"; reference:url,www.group-ib.com/resources/threat-research/red-curl.html; reference:md5,9691daebab79c6ab48adac73bda0a84a; classtype:command-and-control; sid:2030697; rev:4; metadata:attack_target Client_Endpoint, created_at 2020_08_17, deployment Perimeter, deployment SSLDecrypt, deprecation_reason False_Positive, performance_impact Moderate, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_04;)