BlackByte

BlackByte is a ransomware family and ransomware-as-a-service operation active since 2021 that has targeted enterprise environments, including Windows and VMware ESXi systems. It is associated with double-extortion activity in which operators encrypt victim data and steal information for leverage, and mature affiliates have used a dedicated exfiltration utility known as Exbyte to support data theft.

Observed BlackByte intrusions show operators gaining access through exploitation of exposed services and vulnerabilities, including Microsoft Exchange ProxyShell flaws and, more recently, VMware ESXi authentication-bypass vulnerabilities. After initial compromise, operators have used Cobalt Strike, credential dumping, remote access software, and administrative shares to expand access across the environment. BlackByte activity has included reconnaissance of hosts and Active Directory, lateral movement, registry modification to facilitate propagation and remote administration, firewall rule changes, deletion of shadow copies, and disabling or impairing security controls.

BlackByte is also notable for aggressive defense-evasion tradecraft. Reported cases include process injection into legitimate Windows processes prior to encryption and abuse of vulnerable or signed drivers to disable endpoint protections, including campaigns described as BYOVD. Some reporting also links BlackByte operations with multivector extortion tactics that incorporate DDoS pressure alongside ransomware deployment.

The malware has been observed encrypting from injected processes, staging encryption material on adversary-controlled virtual private servers, and deploying ransom notes across compromised systems. BlackByte has affected mid-market and large organizations and has been discussed alongside other major enterprise-focused ransomware operations.