alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE ModPipe CnC Activity (POST)"; flow:established,to_server; http.start; content:"POST /robots.txt HTTP/1."; fast_pattern; http.user_agent; content:"Mozilla/4.0|20|(compatible|3b 20|MSIE 8.0|3b 20|Windows|20|NT|20|6.1|3b 20|Trident/4.0)"; depth:63; isdataat:!1,relative; http.header_names; content:"Accept|0d 0a|Content-Length|0d 0a|Content-Type|0d 0a|User-Agent|0d 0a|Host|0d 0a|Cache-Control|0d 0a 0d 0a|"; reference:url,www.welivesecurity.com/2020/11/12/hungry-data-modpipe-backdoor-hits-pos-software-hospitality-sector/; classtype:command-and-control; sid:2031208; rev:1; metadata:attack_target Client_Endpoint, created_at 2020_11_16, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_16;)