Sandbox (computer security)

In computer security, a sandbox is a security mechanism for separating running programs. It is often used to execute untested code, or untrusted programs from unverified third-parties, suppliers and untrusted users.

The sandbox typically provides a tightly-controlled set of resources for guest programs to run in, such as scratch space on disk and memory. Network access, the ability to inspect the host system or read from input devices are usually disallowed or heavily restricted. In this sense, sandboxes are a specific example of virtualization.

Some examples of sandboxes are:

  • Applets are self-contained programs that run in a virtual machine or scripting language interpreter that does the sandboxing. In application streaming schemes, the applet is downloaded onto a remote client and may begin executing before it arrives in its entirety. Applets are common in web browsers, which use the mechanism to safely execute untrusted code embedded in web pages. Three common applet implementations—Adobe Flash, Java applets and Silverlight—provide (at minimum) a rectangular window with which to interact with the user and some persistent storage (at the user’s permission). Continue reading