What Is Least Privilege Access?
Written by: Chris Tozzi
A basic best practice when configuring roles and permissions for any software environment is to apply least privilege access. By restricting access rights to the minimum required for each user or group to do their job, least privilege access helps to minimize security risks.
Least Privilege Access, Defined
Least privilege access is when you only give a user or group the minimum level of permissions needed to perform a given task.
In other words, when you adhere to the principle of least privilege, you focus on ensuring that no user or group has access rights or permissions that exceed the minimum required to perform their role within the organization.
Least privilege access is sometimes also referred to as minimum privilege access or least authority access.
Benefits of Least Privilege
The main benefit of least privilege is that it restricts the potential damage caused by a security breach.
In an environment where users have access to more resources than they strictly need, anyone who manages to compromise their accounts will likewise have access to those systems. But by restricting access to the minimum necessary, you limit the impact of a breach.
Least privilege access also offers the benefit of making audits more effective. When you follow the principle of least privilege, you can perform audits of your access policies to determine whether any policies give users more access rights than they require. You can then take steps to address the risk.
Example of Least Privilege Access
To understand what least privilege means in practice, consider a cloud environment that is shared by multiple users within an organization. Some of the users are developers, while others are IT engineers. The developers use one set of dev/test VMs to build and test applications. The IT engineers use another to deploy applications for production use.
To configure least privilege access in this scenario, you would configure cloud identity and access management (IAM) roles and policies in such a way that the developers could create, modify, and run only the specific VMs they use for dev/test purposes. Likewise, the IT engineers would only be able to access production VMs.
The opposite of least privilege in this example would be to create IAM rules that give all team members access to all VMs. That may be tempting to do because you may assume that developers might sometimes need to access production VMs, and IT engineers might sometimes want to see what is happening in the dev/test environment. However, this approach would not be optimal from a security perspective because it would increase the potential impact of a security breach. If a developer’s account is compromised, for instance, the attackers would be able to access all VMs in the environment if the account has access to all of them. But with least privilege access in place, only the dev/test environments would be exposed.
Least Privilege vs. Zero Trust
Least privilege access is similar to, but distinct from, the principle of zero trust.
Zero trust means not assigning any access rights to a user, group, or other resource until you have verified that the entity can be trusted. This is another way to help mitigate the risk of breaches. However, zero trust is different from least privilege access because you need to establish trust before you can apply least privilege access. Until trust has been established, no access rights can be enabled at all under the zero trust model.
Managing Least Privilege Access
The main challenge associated with setting up and managing least privilege access is determining which access rights each user or group actually needs, then creating policies that enforce those rights. You must also ensure that least privilege remains in place as the access needs of users and groups change and policies are updated.
Staying on top of all of this information manually is a challenge. To streamline the process, teams can scan IAM configurations within their environments to determine which access rights are assigned to whom, and whether anyone has unnecessary levels of access to any resources. Automatic and continuous scanning of access rules helps prevent accidental oversights that could lead to unnecessary security exposures.