alert icmp any any -> any any (msg:"ET MALWARE Possible ICMP Backdoor Tunnel Command - whoami"; itype:8; icode:0; content:"whoami"; depth:6; nocase; reference:url,www.hackingarticles.in/command-and-control-tunnelling-via-icmp; classtype:trojan-activity; sid:2027763; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_07_29, deployment Perimeter, performance_impact Moderate, confidence Medium, signature_severity Major, updated_at 2019_07_29;)