alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Yahoyah CnC Beacon"; flow:established,to_server; http.user_agent; content:"MSIE|28|"; startswith; content:"|29 29 3b 20|NT|28|"; distance:0; content:"|29 3b 20|AV|28|"; fast_pattern; distance:0; content:"|29 3b 20|OV|28|"; distance:0; content:"|29 3b 20|NA|28|"; distance:0; content:"|29 20|VR|28|"; distance:0; http.header_names; content:!"|0d 0a|Accept"; content:!"|0d 0a|Referer|0d 0a|"; reference:url,trendmicro.com/cloud-content/us/pdfs/security-intelligence/white-papers/wp-operation-tropic-trooper.pdf; classtype:command-and-control; sid:2021114; rev:4; metadata:attack_target Client_Endpoint, created_at 2015_05_18, deployment Perimeter, signature_severity Major, tag c2, updated_at 2024_03_10, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)