alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING Possible NOBELIUM CnC Traffic (Observed UA)"; flow:established,to_server; http.method; content:"GET"; http.user_agent; bsize:101; content:"Mozilla|2f|5|2e|0|20 28|Windows|20|NT|20|6|2e|2|29 20|AppleWebKit|2f|537|2e|36|20 28|KHTML|2c 20|like|20|Gecko|29 20|Chrome|2f|90|2e|0|2e|4430|2e|85|20|Safari|2f|537|2e|36"; fast_pattern; http.content_type; bsize:9; content:"text/html"; http.header; header_lowercase; content:"cache-control|3a 20|no-cache"; reference:url,www.sekoia.io/en/nobeliums-envyscout-infection-chain-goes-in-the-registry-targeting-embassies; classtype:bad-unknown; sid:2034870; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_12_07, deployment Perimeter, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_30;)