alert tcp-pkt $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE CHStealer checkping Command CnC Checkin"; flow:established,to_client; dsize:<50; content:"/checkping"; fast_pattern; endswith; reference:md5,2a091a17e58b609faebf0e349c7d0b63; classtype:trojan-activity; sid:2061720; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_and_Server, tls_state plaintext, created_at 2025_04_17, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_04_17, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel; target:dest_ip;)