alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MaskGramStealer Common Victim C2 Response (POST)"; flow:established,to_server; http.method; content:"POST"; http.user_agent; bsize:10; content:"Client/1.0"; fast_pattern; http.content_type; content:"application/x-www-form-urlencoded"; http.request_body; bsize:<17; pcre:"/^(?:ftpclients|wallets|mailclients|svit|telegram|discord)\x3d(?:nepco|true|false)$/"; reference:md5,25041e230c55fd46e5ef52ab02b3bc6c; classtype:command-and-control; sid:2066663; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_01_09, deployment Perimeter, deployment SSLDecrypt, malware_family MaskGramStealer, signature_severity Critical, updated_at 2026_01_09; target:src_ip;)