ET HUNTING Possible NOBELIUM CnC Traffic (Observed UA)

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;
    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"; bsize:101; fast_pattern;
    http.content_type;
    content:"text/html"; bsize:9;
    http.header;
    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:3;
    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 2022_01_10;
)