alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/DeerStealer CnC Checkin"; flow:established,to_server; http.method; content:"POST"; http.uri; pcre:"/^.+\x3f[a-zA-Z0-9]{8,20}\x3d[a-zA-Z0-9+\x2f=]{30,200}$/"; http.content_len; byte_test:0,=,96,0,string,dec; http.header_names; bsize:58; content:"|0d 0a|Connection|0d 0a|Accept|0d 0a|User-Agent|0d 0a|Content-Length|0d 0a|Host|0d 0a 0d 0a|"; http.request_body; content:"|a0 a0 a0 ff ff d9 24|"; fast_pattern; pcre:"/^[a-f0-9]{8}-(?:[a-f0-9]{4}-){3}[a-f0-9]{12}/R"; reference:md5,6574d8e01ed5e76fbe7ede634f728c92; reference:md5,fa79b4a698424f36518f80a50c485561; reference:md5,db680e1ecbfca3baf196704c572f1296; classtype:trojan-activity; sid:2056550; rev:1; metadata:attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2024_10_08, deployment Perimeter, deployment SSLDecrypt, malware_family DeerStealer, performance_impact Low, confidence High, signature_severity Major, updated_at 2024_10_08; target:src_ip;)