The Principle of Least Privilege is the idea of providing the lowest level of access to all user accounts to reduce privileges to resources, systems, and networks. Only user accounts that require access to the specified resource are given access. Additionally, access is only given when it is needed, and then it is revoked. 

For example, if a specific user account exists to allow an employee to back up their data to a corporate server, they are only given privileges related to backing up their data. They are not given rights to install new apps and might not even be given access to view data, depending on the needs of the user.

While user accounts are typically in the spotlight when discussing the principle of least privilege, this philosophy also calls for running all applications with as few rights as possible. All applications will need some level of rights to operate, so they are given exactly the rights they need to operate and nothing further.

Cybercriminals are well aware that many enterprises use third-party applications and services that are integrated with internal systems. They study these third-party applications and their integrations to look for security flaws. Once found, they are exploited, and they may gain access to internal data. PoLP exists to restrict the level of access that third-party applications are given, greatly reducing this threat.

Benefits of the Principle of Least Privilege

• Better security: Edward Snowden was able to leak millions of NSA files because he had admin privileges, though his highest-level task was creating database backups. Since the Snowden leaks, the NSA has employed the principle of least privilege to revoke higher-level powers from 90% of its employees.

• Minimized attack surface: Hackers gained access to 70 million Target customer accounts through an HVAC contractor who had permission to upload executables. By failing to follow the principle of least privilege, Target had created a very broad attack surface.

• Limited malware propagation: Malware that infects a system bolstered by the principle of least privilege is often contained to the small section where it entered first.

• Better stability: Beyond security, the principle of least privilege also bolsters system stability by limiting the effects of changes to the zone in which they’re made.

• Improved audit readiness: The scope of an audit can be reduced dramatically when the system being audited is built on the principle of least privilege. What’s more, many common regulations call for POLP implementation as a compliance requirement.