What is the principle of least privilege (POLP)?

The principle of least privilege (POLP) is a cybersecurity approach, where users have access to only the data and resources they require to perform their daily job. This principle is also called the principle of minimal privilege, access control principle and the principle of least authority.

When your organization operates by the principle of least privilege, users are granted the bare minimum of privileges to resources such as networks, systems and applications. By establishing least privilege in the context of a Zero Trust security model, organizations will significantly mitigate the risk of compromise, breach and authorize access to high-value data. For example, does your organization’s marketing managers need access to your software development environment? Of course not. Similarly, do your software developers need access to payroll data? No. Following the principle of least privilege, both user groups will only have permissions needed for their basic job functions.

Note that the principle of least privilege applies to all access: by humans and non-human (machine) users, such as devices, bots and software applications. In an era of booming demand for credentials and data sharing, threat actors are probing for weaknesses in your network and apps. Identity sprawl is the downside of easier interoperability that the transition to cloud-based resources offers. This interoperability is another reason to implement Zero Trust, so that no user is granted more permissions than those required to execute approved tasks. Anything more increases the cybersecurity exposure gap of an organization.

How can you enforce the principle of least privilege with human and non-human users without jeopardizing security, compliance or user productivity? That requires a comprehensive system that can continuously manage and validate privileges.

Least privilege is an important part of security because limiting user permissions to necessary accounts and resources helps to mitigate the risk of a data breach. This cyber defense tactic eliminates vulnerabilities by managing user permissions provisioning with tools – like Microsoft Active Directory - that also manages privileged user data and access rights to critical digital resources. When combined with other measure such as secure single sign-on, multifactor authentication, solid cybersecurity training practices and policy enforcement, least privilege is a powerful protectant against breaches and other threat-actor activities.

For example, suppose attackers obtain the credentials of an employee account with few permissions. When they log in as that employee, they will have only limited system access. So, the damage ( “blast radius”) is contained. However, when those attackers compromise an administrator account with privileged access rights and potentially unlimited access, the attackers cause catastrophic damage.

That’s why observing least privilege offers multiple benefits and affects data security in several important ways. Please note that least privilege – and Zero Trust policies – also apply to admin/privileged users as well – and is more critical in the admin realm with their elevated access rights.

1. Reduced attack surface and enhanced security

With many organizations like yours making the digital transformation, the attack surface is increasing in size and vulnerability. The move to the cloud causes organizations to operate hybrid IT environments, which has digital resources operating on-premises and the cloud with different identity and access management (IAM) systems and processes for each. This provides more opportunity for threats to find a weakness to exploit. On top of moving to the cloud, there’s also other complicating factors, such as the increase in remote working, the growing reliance on contractors and third parties to manage critical corporate functions. The attack surface continues to grow. Least privilege keeps the attack surface as small as possible, by restricting access and permissions to those who need them.

2. Helps stop the spread of malware

Maintaining the principle of least privilege helps to limit the impact of malware attacks. For example, if an employee clicks a link in a phishing email, the attack is limited to the accounts and permissions of that employee and won’t spread too far laterally. However, if that employee has super admin or root access privileges, the attack will likely spread throughout the entire network. By giving users only the permissions they need, your organization is better protected from cyberattacks.

3. Improves performance for users and systems

The practice of granting users just the permissions they need leads to improved productivity and fewer troubleshooting requests. And, by limiting the potential impact of a breach, a least-privilege approach improves the stability of the organization’s systems in the event of an attack.

The least privilege concept reduces the attack surface and lessens the potential harm from hostile forces, which enhances performance for users and systems. Encryption, security guidelines, firewalls, and other systems can function more effectively and efficiently to safeguard the system from unwanted or destructive acts by only allowing essential access to data and processes.

4. Streamlines compliance and audits

If your organization collects, stores and uses sensitive data, you must comply with regulations, such as GDPR, HIPAA, PCI DSS and SOX, to ensure it is being handled properly. Those regulations require that you enforce least-privilege access policies. Limiting access to users in specific roles makes compliance easier. Plus, it’s easier to pass audits when least-privilege is implemented and audit trails are in place for privileged activity.

Many organizations establish least-privilege policies in the course of deploying a Zero Trust cybersecurity model. Here are the main steps in the process:

Conduct an audit

To ensure that accounts have least-privilege permissions, it’s important to audit and know the current state of access in your organization. The goal is to verify that employees, third-party users, devices, applications and robotic processes have only the permissions needed to complete their tasks on only the intended network resources.

Start all accounts with least privilege

All account privileges must start as low as possible. Where additional access is necessary, add the appropriate permission as needed. Remove higher-level permissions from accounts that don’t need them. With role-based access control, the business will easily set guidelines for positions and roles, in order to create groups to expedite provisioning and better ensure that users have the right permissions required for a given task or responsibility.

Maintain separate privileges for privileged and standard access

To limit access when a breach occurs, administrator and standard-user access – even for a user that has both – must be separate at all times. For an additional security layer with admins, split high-level system functions — reading, writing and executing to databases and applications — from lower-level functions. Do the same for auditing and logging privileges. This separation of duties (SoD) ensures that no one user (human or machine) can have unlimited access, where one set of credentials are compromised, the potential damage is limited by least privilege.

Limit access to higher privileges

Restrict access to increased privileges and temporarily grant elevated permissions on an as-needed basis. When a user temporarily needs higher or additional access to a privileged environment, allow access through one-time-use credentials or through session privileges with timed expiration.

Keep track of individual actions

Track and monitor access to your sensitive assets, such as employee records and customer data. That enables detection of unusual activity and anomalies, as well as ensures individual accountability.

Continuously review privileges

Conducting regular audits and re-certification campaigns helps to keep user privileges at correct levels. Over time, users and accounts can accumulate elevated privileges that are no longer used or necessary. A regular review keeps identity sprawl and privilege creep in check.

Too much access. Where a user – even a privileged user – has access to every resource in an environment such as from applications and data to backend infrastructure, that’s access is a major vulnerability for an organization. Admins and privileged access are the primary target of hackers. If privileged credentials are compromised, the potential damage by a data breach or malware is catastrophic to an organization. Newer regulations mean expensive fines for companies if personally identifiable information (PII) is accessed. So, a standard line-of-business user who has standing rights to a critical database because they need quarterly access to that information, violates the principle of least privilege. In short, users must only have the bare minimum access rights to do their daily job, beyond that they will need to go through an approval process, or a monitored session protocol to ensure individual accountability and to protect the data and the organization as a whole. Just in time access, allows permission levels to be more fluid and dynamic, so that privileges are only assigned as and when needed, then rescinded when no longer in use.

The accumulation of rights as a user changes jobs or responsibilities at an organization is a violation of least privilege. With each job change, a user’s permissions must be verified as compliant, so that all access rights are verified, needed and appropriate. This keeps your user data clean and elevates your cybersecurity, protects against internal threat, and ensures least privilege is maintained.

Privileged Access Management (PAM) is an IT security best practice that protects identities with administrative permissions and capabilities beyond standard users. As with all cybersecurity solutions, PAM works through a combination of people, processes and technology.

Privileged accounts must be treated with extra care because they post a heightened risk if they are compromised. Privileged users – called ‘admins’ – often have elevated access to critical systems and resources, such as financial and customer data, as well as operational tools to manage the core functions of an organization. For example, when the credentials of an administrator or service account fall into the wrong hands, it leads to exfiltration of the organization's systems and confidential data.

Privilege credentials and their access are the ultimate target of threat actors as these accounts hold the keys that unlock every door in a technology environment, we need to add additional layers of protection.