jailbreak
also: container escape, sandbox escape, breakout
A technique to escape or bypass security restrictions imposed by a container, virtual machine, or sandboxed environment to gain unauthorized access to the host system.
A jailbreak occurs when an attacker exploits vulnerabilities in isolation mechanisms—such as Docker containers, chroot jails, VMs, or SELinux policies—to break out and access the underlying host operating system. This undermines the security boundary meant to confine applications or users.
For example, if a compromised application running in a Docker container finds a kernel vulnerability, it might execute arbitrary code on the host. Similarly, a user in a restricted chroot environment could exploit a flaw to access files and processes outside the intended directory tree.
Common jailbreak vectors include kernel exploits, misconfigured container capabilities, symlink attacks, and privilege escalation bugs. Preventing jailbreaks requires keeping the kernel and container runtime patched, minimizing unnecessary privileges, and using proper security modules like AppArmor or SELinux.