A setuid binary, also known as a set-user-ID binary, is a specialized type of executable file in Unix-like operating systems. It enables a program to execute with the privileges of the file owner or a specific user/group, rather than inheriting the privileges of the user running the file. The term “uid” in “setuid” stands for user ID.

When a setuid binary is executed, it temporarily changes the effective user ID (EUID) of the process to match that of the binary’s owner. This allows the process to perform actions or access resources typically restricted to the owner’s privileges, effectively elevating the process’s privileges for the duration of its execution.

Setuid binaries find use in system administration tasks and operations requiring elevated privileges, such as managing network interfaces, modifying system files, or accessing sensitive information. Examples include programs like passwd (for changing passwords) and sudo (for executing commands with elevated privileges).

Given the potential security risks associated with setuid binaries, strict measures are in place to ensure their safe use. This involves careful programming and thorough testing to prevent unauthorized access or misuse of elevated privileges. System administrators should review and maintain setuid binaries regularly to minimize potential security vulnerabilities.

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