alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET RETIRED BunnyLoader Heartbeat Acknowledgement"; flow:established,to_client; flowbits:isset,ET.BunnyLoader.Heartbeat; http.stat_code; content:"200"; http.content_len; byte_test:0,=,13,0,string,dec; http.response_body; content:"Client|20|online"; fast_pattern; threshold:type limit, track by_src, count 1, seconds 300; reference:url,www.zscaler.com/blogs/security-research/bunnyloader-newest-malware-service; reference:md5,dbf727e1effc3631ae634d95a0d88bf3; classtype:trojan-activity; sid:2048403; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, created_at 2023_10_04, deployment Perimeter, former_category MALWARE, malware_family BunnyLoader, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_05_19, reviewed_at 2023_10_04; target:dest_ip;)