In computer security, a sandbox is a security mechanism for separating running programs, usually in an effort to mitigate system failures and/or software vulnerabilities from spreading. The isolation metaphor is taken from the idea of children who do not play well together, so each is given their own sandbox to play in alone. It is often used to execute untested or untrusted programs or code, possibly from unverified or untrusted third parties, suppliers, users or websites, without risking harm to the host machine or operating system. A sandbox typically provides a tightly controlled set of resources for guest programs to run in, such as storage and memory scratch space. Network access, the ability to inspect the host system, or read from input devices are usually disallowed or heavily restricted. In the sense of providing a highly controlled environment, sandboxes may be seen as a specific example of virtualization. Sandboxing is frequently used to test unverified programs that may contain a virus or other malicious code without allowing the software to harm the host device. Implementations A sandbox is implemented by executing the software in a restricted operating system environment, thus controlling the resources (e.g. file descriptors, memory, file system space, etc.) that a process may use. Examples of sandbox implementations include the following: Linux application sandboxing, built on Seccomp, cgroups and Linux namespaces. Notably used by Systemd, Google Chrome, Firefox, Firejail. Android was the first mainstream operating system to implement full application sandboxing, built by assigning each application its own Linux user ID. Apple App Sandbox is required for apps distributed through Apple's Mac App Store and iOS/iPadOS App Store, and recommended for other signed apps. Windows Vista and later editions include a "low" mode process running, known as "User Account Control" (UAC), which only allows writing in a specific directory and registry keys. Windows 10 Pro, from version 1903, provides a feature known as Windows Sandbox. Google Sandboxed API. Virtual machines emulate a complete host computer, on which a conventional operating system may boot and run as on actual hardware. The guest operating system runs sandboxed in the sense that it does not function natively on the host and can only access host resources through the emulator. A jail: network-access restrictions, and a restricted file system namespace. Jails are most commonly used in virtual hosting. Rule-based execution gives users full control over what processes are started, spawned (by other