alert http $EXTERNAL_NET any -> $HOME_NET any (
msg:"ET MALWARE Win32/keyzetsu Stealer exfil via Telegram (Response)";
flow:established,to_client;
file.data;
content:"|7b 22 6f 6b 22 3a 74 72 75 65 2c 22 72 65 73 75 6c 74 22 3a 7b 22 6d 65 73 73 61 67 65 5f 69 64 22 3a|"; startswith;
content:"|22 75 73 65 72 6e 61 6d 65 22 3a 22 6b 65 79 7a 65 74 73 75 5f 62 6f 74 22 7d|"; fast_pattern; distance:0;
reference:md5,1af3a0709eda27160766cddde28815fd;
reference:md5,121fad4583d975de6e511bb71660fad8;
reference:url,twitter.com/suyog41/status/1636014180787445760;
classtype:trojan-activity;
sid:2044692; rev:2;
metadata:attack_target Client_Endpoint, created_at 2023_03_20, deployment Perimeter, deployment SSLDecrypt, malware_family Win32_keyzetsu, performance_impact Low, confidence High, signature_severity Critical, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_05_30;
target:dest_ip;
)