Implementing a Least Privilege Strategy in Your Organization

The principle of least privilege (POLP) is one of the most fundamental tenets in securing IT environments. It requires giving each user, service and application exactly the access to data, systems and other network resources that they need to perform their work.

This guide explains the benefits and limitations of this core principle and details the key steps for implementing it.

Benefits of Least Privilege

Stronger Security

Limiting each user's permissions to only what is strictly necessary shrinks the attack surface of your critical systems. In particular, POLP reduces the risk of both unintentional and malicious use of data and applications, whether those actions originate from the users themselves or from external attackers who have compromised their credentials.

For example, POLP reduces the risk of ransomware infection, since most user accounts won’t have the administrative privileges required to install the malware. And even if it does execute, it will be able to encrypt only the data that the user account has access to, so enforcing POLP reduces the damage that can be inflicted.

Regulatory Compliance

Enforcing the principle of least privilege also plays a critical role in the achieving and maintaining compliance. Many regulatory standards require organizations to limit access to sensitive data based on their job functions, especially for users with privileged access.

Limitations of Least Privilege

Implementing the POPL is a best practice for every organization, but it is just one aspect of a comprehensive, defense-in-depth security strategy. In addition to limiting access rights, organizations need to take other steps to reduce their attack surface area, including configuration management and regular patching of all software. Moreover, they need to audit and analyze activity to promptly identify potential threats, and implement robust incident response and recovery plans.

Implementing the Principle of Least Privilege

Create the Right Accounts

The principle of least privilege requires granting each identity exactly the access rights it requires. There are three core types of user identities:

Business users — Most user accounts are assigned to individuals who need limited access to a selected set of network resources.
Privileged users — Some individuals need more powerful accounts. They fall into two categories. The first is people who need access to certain sensitive data and services, such as account managers or the finance team. The second is IT administrators, who need to access and modify core systems and data; the most highly privileged user accounts have complete control across the environment. These individuals should also be assigned a regular business user account that they should use for any tasks that do not require administrator privileges.
Service accounts — Some user accounts are assigned not to humans but to applications, such as web servers, databases, email solutions and cloudservices. To enforce the principle of least privilege, you need to carefully assess each application's specific access needs and create a service account with the minimum necessary privileges.

Consider Using a Role-Based Model

Adopting role-basedaccess control (RBAC) helps organizations follow the principle of least privilege. Here are the essential steps:

Identify the various roles in your organizations. Often roles align with both department and specific job function. For example, two roles might be IT Manager and Helpdesk Technician.
Determine the access rights that are needed for each role.
Assign each user account the appropriate roles.

This approach dramatically simplifies user rights management. When a user joins the organization, they can quickly be granted the access they need simply by assigning them the appropriate roles. If a user moves to a new department, enforcing the POLP is a matter of removing old role assignments and assigning new ones.

Implement Other Access Control Measures

To rigorously enforce least privilege, consider implementing the following additional controls:

Ensure that a user’s account is disabled immediately when they leave the organization and deleted according to your policy. For more information, read our user termination best practices.
For users with a consistent schedule, restrict operational access to their accounts to align with their normal working hours.
When possible, apply location-based restrictions that allow use of accounts from specified locations only.
Consider allowing access to sensitive data and systems exclusively from company-managed computers that are subject to stringent governance policies.

Two additional strategies can complement your POLP strategy by helping to keep intruders out of your network:

Apply an account lockout policy aligned with account lockout best practices.
Implement a strict password policy that requires strong, unique passwords and follows other password best practices.

Audit Access Rights

It’s vital to understand that enforcing the principle of least privilege is a not a one-time event but a continual process. Two particular threats to watch out for are:

Privilege creep — As users change roles within the organization, they often accumulate excessive access rights over time. While RBAC reduces this risk, regular review of permissions is also necessary.
Privilege escalation — Adversaries often gain a foothold in a network by compromising the credentials of a regular business user account. If the POLP is being enforced, that account will not grant them access to the sensitive data and systems they seek, so they look for ways to increase their access rights. Accordingly, it’s essential to be on the lookout for any unexpected changes to an account’s permissions, as well as any change to the permissions granted to a role. Ideally, ensure that you are alerted about all critical changes.

For efficient auditing of account usage and privileges, consider a third-party tool such as Netwrix Auditor. Netwrix Auditor provides comprehensive reports on all changes and alerts you to critical events such as modification of the membership of administrative groups. In addition, it helps you spot and remediate excessive permissions to rigorously enforce the principle of least privilege.

Conclusion

The principle of least privilege is a cornerstone of a robust and resilient cybersecurity framework for your organization. Implementing it demands careful planning and unwavering commitment, but the payoff can be substantial. By adhering to this principle, you can fortify your defenses against both external attacks and internal threats, and also help ensure compliance with regulatory standards.