The principle of least privilege (PoLP) is one of the most important concepts underpinning a strong, structured, and compliant approach to information security.
It asserts that each user and computer process within an environment should only have access rights to the IT resources absolutely necessary to fulfill its role. This rule has two major benefits: It reduces the risk of error and reduces the surface area that a potential cyberattack can traverse.
In practice, the concept of least privilege has two similar-but-distinct applications: one as a best practice in code design at the software engineering level, and another as a user management best practice in the context of system and network administration. We’ll focus on the user management aspect in this article.
What Is the Principle of Least Privilege?
With least privilege as a guideline for user provisioning, each employee only has access to the apps, files, networks, and other resources they need to do their job.
An accountant’s role, for example, doesn’t require access to engineering resources, and providing that access opens an unnecessary pathway for a threat to propagate. Likewise, write/delete permissions for critical data in shared file locations should be exclusive to a select few high-level employees.
Why Enforce Least Privilege Access?
Least privilege user access helps contain a potential cyberattack to a smaller set of resources than might otherwise be compromised. Where a hacked admin account could provide a gateway to a company’s entire network and all its core data, a user account with limited privileges should be relatively unattractive to attackers.
Authorizing each employee to the minimum number of work-essential IT resources can also reduce the risk of user error when editing, organizing, or sharing files.
And it’s not just a preventative measure: With the right monitoring procedures in place, a least-privilege model can help you detect, trace, and mitigate the effects of a cyberattack before it propagates beyond the originally compromised account(s).
Paired with a mechanism to instantly suspend user access to all IT resources, a least-privilege approach can mean increased resilience in the face of a data breach.
For these reasons, least privilege access is regarded as a near-universal security baseline. All major industry compliance schema require IT departments to demonstrate some version of the concept in terms of segmented user access.
If part of your job is to improve your organization’s security posture, implementing a consistent authorization policy around the concept of least privilege is a critical step.
Requirements for Least Privilege User Access
Because each organization’s needs differ, enforcement of the principle of least privilege can vary a bit in scope.
It’s hard to predict a user’s exact needs, and given the amount of flexibility and cross-functional collaboration in modern environments, admins almost always provision users with rights to access more resources than they’ll need on a daily basis. Still, the following core requirements should apply:
- Don’t give end users administrator permissions on their Mac, Windows, or Linux systems.
- Don’t give users top-level author/editor rights in SaaS apps or on your website.
- Segment network access for critical resources; keep dev infrastructure separate from your primary office network.
- Don’t give users broad permissions for apps and resources they’ll only use occasionally. Instead, have a system in place to augment permissions on an as-needed basis, then revoke them when the task at hand is complete.
- For IT admins, consider only logging in as a network or domain admin when absolutely necessary; instead perform day-to-day tasks from a basic user account.
- Implement continuous monitoring of user accounts, permissions, and app usage information.
- Ensure that any unused accounts from deprovisioned users are detected and closed.
These permissions rules may sound like common sense in theory, but some of them require a bit of legwork to reliably implement and monitor.
How to Implement a Least Privilege Authorization Framework
Depending on the size of your organization, you may be able to manage user access manually while meeting compliance requirements. But as headcount grows and positions turn over, you’ll need a system in place to make sure that user provisioning, deprovisioning, and role changes can be reliably tracked.
Spreadsheets and checklists are a start, though as you spend more time manually managing user authorization, automated solutions start to look more attractive.
At scale, the most secure and efficient tool for controlling user permissions is the directory service, which houses user identities and their associated access privileges. Microsoft Active Directory (AD) has historically filled this role for on-prem Windows environments, acting as the source of truth against which users authenticate to their workstations, networks, file servers, and apps.
AD’s user groups allow admins to grant and revoke bulk access to IT resources — by department, for example. AD also lets the administrator deploy GPOs to enforce group policy, like disabling certain write permissions, on Windows systems.
But if your environment includes Mac or Linux systems, cloud infrastructure, or third-party SaaS apps, user management with AD can quickly become a headache. It’s not uncommon for a Windows shop to add 10 MacBooks to the fleet and quietly let those users keep admin privileges on their machines.
This scenario might be more or less manageable, but it’s neither secure nor compliant. You may want to look into a modern directory solution to enforce the principle of least privilege throughout your heterogeneous environment.
Centralized User Management With A Cloud Directory Service
A cloud directory service gives admins the level of control over user access once afforded by on-prem AD, but for the whole spectrum of modern IT resources.
With a cloud directory in place of AD, you can remotely push GPO-like system policies to Mac and Linux machines, manage user access to cloud infrastructure, authorize user groups to SaaS apps, segment network access with cloud-hosted RADIUS servers, and more. Learn more about managing user privileges with a cloud directory.