alert http1 $HOME_NET any -> $EXTERNAL_NET 1024: (msg:"ET MALWARE Possible Raspberry Robin Activity (GET)"; flow:established,to_server; urilen:>25; http.method; content:"GET"; http.uri; pcre:"/^\/[A-Za-z0-9]{10,11}\//"; content:!"|2e|"; http.header; content:"Connection|3a 20|Keep|2d|Alive|0d 0a|Accept|3a 20 2a 2f 2a 0d 0a|User|2d|Agent|3a 20|Windows|20|Installer|0d 0a|Host|3a 20|"; startswith; fast_pattern; http.header_names; bsize:42; content:"|0d 0a|Connection|0d 0a|Accept|0d 0a|User-Agent|0d 0a|Host|0d 0a 0d 0a|"; reference:md5,0bdae8ec9a8fd2a6dd9a39eae00c9834; reference:url,redcanary.com/blog/raspberry-robin; classtype:trojan-activity; sid:2037761; rev:5; metadata:attack_target Client_Endpoint, created_at 2022_01_20, deployment Perimeter, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_03, reviewed_at 2023_08_25;)