ESXiArgs is a ransomware campaign that emerged in February 2023, targeting VMware ESXi servers by exploiting the CVE-2021-21974 vulnerability. It encrypts virtual machine configuration files (.vmdk, .vmx, .vmxf, .vmsd, .vmsn, .vswp, .vmss, .nvram, .vmem) rendering VMs inaccessible. The campaign compromised thousands of unpatched servers globally, primarily affecting European organizations. A decryptor was later released by CISA and FBI.