ET MALWARE Suspected Kapeka/ICYWELL Backdoor Server Response (read from file)

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Suspected Kapeka/ICYWELL Backdoor Server Response (read from file)";
    flow:established,to_client;
    file.data;
    content:"|3a 20 22|Read|20|from|20|file|22|,"; fast_pattern;
    content:"|3a 20 22|C|3a 2f 2f|"; distance:0;
    reference:url,labs.withsecure.com/content/dam/labs/docs/WithSecure-Research-Kapeka.pdf;
    reference:url,services.google.com/fh/files/misc/apt44-unearthing-sandworm.pdf;
    classtype:trojan-activity;
    sid:2052173; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2024_04_19, deployment Perimeter, deployment SSLDecrypt, malware_family SANDWORM, malware_family APT44, confidence Medium, signature_severity Major, tag RAT, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_19;
    target:dest_ip;
)