alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Donot Group Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; pcre:"/^\/[A-Za-z0-9]{21}\/[A-Za-z0-9]{17,20}$/"; http.header_names; content:"|0d 0a|Accept|0d 0a|User-Agent|0d 0a|Host|0d 0a 0d 0a|"; fast_pattern; bsize:30; http.user_agent; content:!"Mozilla"; content:!"Linux"; classtype:trojan-activity; sid:2045124; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_04_21, deployment Perimeter, deployment SSLDecrypt, performance_impact Moderate, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_04_21; target:src_ip;)