alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Activity (GET)"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"/r-arrow"; startswith; fast_pattern; http.user_agent; content:"Mozilla|2f|5|2e|0|20 28|Windows|20|NT|20|10|2e|0|3b 20|Win64|3b 20|x64|29 20|AppleWebKit|2f|537|2e|36|20 28|KHTML|2c 20|like|20|Gecko|29 20|Chrome|2f|42|2e|0|2e|2311|2e|135|20|Safari|2f|537|2e|36|20|Edge|2f|12|2e|246"; bsize:127; http.header_names; content:!"Referer"; reference:md5,2157d05171e0a32c30a8c8350d25335a; classtype:trojan-activity; sid:2043416; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_01_19, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_01_19;)