alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE AtlasAgent Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/orders?session="; startswith; fast_pattern; content:"--"; endswith; within:20; http.header_names; content:"|0d 0a|Content-Type|0d 0a|User-Agent|0d 0a|"; startswith; content:!"Referer"; reference:md5,ba85467ceff628be8b4f0e2da2a5990c; reference:url,nsfocusglobal.com/warning-newly-discovered-apt-attacker-atlascross-exploits-red-cross-blood-drive-phishing-for-cyberattack/; classtype:command-and-control; sid:2048358; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_09_28, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_09_29, reviewed_at 2023_09_29; target:src_ip;)