Least Privilege Access: Fewer Permissions, More Security

The principle of least privilege is an IT security best practice that requires organizations to restrict the permissions of each user and application account to the minimum level required to complete their tasks. Enforcing least privilege access reduces the risk and potential impact of cyber attacks, but requires permission policies and regular audits. In this article, we will examine the advantages of least privilege access, what sets it apart from similar concepts like need to know and how organizations can implement the principle of least privilege on their network.

What Is the Principle of Least Privilege?

The principle of least privilege, also known as the principle of least authority or minimal privilege is a concept from information security. It is based on the idea of limiting IT privileges to the minimum level needed for a specific job. This applies to user accounts, device accounts, applications and so on.

Similar to zero trust, the principle of least privilege treats IT permissions as a potential danger. Access to files and systems can become a liability when faced with insider threats like employee data theft, malware spreading through the network or if an attacker manages to take over an account. Therefore, restricting permissions to the lowest possible level lowers the risk of data breaches.

To enforce the principle of least privilege, organizations need to reduce the initial privileges granted to each employee and carry out regular user access reviews to prevent unnecessary privileges from accumulating over time.

NIST, the National Institute of Standards and Technology, gives this official least privilege definition: “The principle that a security architecture should be designed so that each entity is granted the minimum system resources and authorizations it needs to perform its function.”

Least Privilege vs Need to Know

The terms least privilege and need to know are often used interchangeably. In fact, the two concepts have a lot in common: similar to the principle of least privilege, information that is kept need-to-know is shared with as few people as possible, so that only individuals who genuinely need to information have access to it.

However, there are two important differences between least privilege and need to know:

  • 1

    Need to know only limits who has access, while least privilege also restricts what they can do (view, edit, execute, etc.)

  • 2

    Need to know only covers people, while least privilege extends to applications, devices and service accounts.

As you can see, least privilege goes further than need to know access because it requires organizations to stick to the lowest permission level possible (such as read-only) and covers non-human accounts in an IT environment.

Least Privilege vs Segregation of Duties

Segregation of duties (SOD) is based on the idea that no single user should be able to act without supervision. To prevent fraud and conflicts of interest, organizations need to split certain tasks between multiple people. For example, the same person cannot submit expense reports and then approve them for reimbursement.

Segregation of duties adds another layer of complexity to access rights management by requiring organizations to consider how privileges interact. Permissions that are fine on their own and meet the least privilege standard can still be a problem when put together. To avoid this issue, companies need to implement safeguards to prevent users from holding incompatible permissions.

Privilege Creep: Where Unnecessary Permissions Come From

At this point you may be wondering: How do users end up with unnecessary privileges? Do companies simply provide their employees with too much access? Well, this can happen when organizations do not have a granular access policy, meaning that all staff can access all data – like the hospital that was fined under the GDPR because medical information was open to all IT accounts, from doctors to administrators and facility managers.

Frustrated sysadmin discovering overprivileged users on their network.
Where did all these permissions come from?! With least privilege, this wouldn’t have happened! Adobe Stock, (c) kues1

The more common scenario, however, are privileges that once served a purpose but remain active for too long. For example, an employee might switch to a new department, but keep the permissions from their old position. The problem isn’t that they weren’t meant to have these privileges, it’s that they were not removed once they became outdated. In organizations that do not audit access, users accumulate permissions over time from projects, collaborations, temporary assignments. This process is also known as privilege creep.

Another way employees receive unwanted privileges is through the reliance on reference users for provisioning new accounts.

Why Is The Principle of Least Privilege So Important?

Implementing least privilege access offers many operative, security and compliance benefits. The principle of least privilege allows you to

  • Reduce your attack surface: Alongside outdated permissions, least privilege access also requires organizations to eliminate inactive accounts, such as orphaned accounts left behind when employees leave. Since abandoned accounts are popular attack vector, removing them reduces the risk of cyberattacks.

  • Minimize breaches: Unfortunately, there is no such thing as perfect security. While organizations need to do everything they can to prevent data breaches, they also need to prepare for the worst case scenario of a successful attack. If one of your accounts falls into the wrong hands, least privilege minimizes the security impact by restricting the services and resources exposed to malware or hackers. Ideally, this prevents them from accessing other parts of your network, but it will at the very least slow them down.

  • Prevent data misuse: Many security incidents start within an organization. This can include intentional acts like theft or sabotage, as well as reckless behaviour by employees. By preventing your staff from accessing critical files, you also stop them from accidentally leaking information by emailing the wrong file to a client.

  • Improve compliance: Least privilege access is a key requirement of many cybersecurity standards and regulations, including the GDPR, SOX, HIPAA, NIST CSF and ISO 27001. Even norms that don’t mention least privilege access by name often require it in practice by mandating stringent access control and periodic audits.

How to Implement Least Privilege Access

Maintaining the principle of least privilege is an ongoing process that requires organizations to continuously re-evaluate the permissions, resources and applications of both new and existing accounts. Transitioning to a least privilege model involves a several steps, which we have outlined below.

While it is technically possible to complete the necessary changes and audits by hand, the only realistic way to achieve least privilege in an organization with more than a few dozen employees is through an identity and access management solution like tenfold. Read on to learn how IAM software can assist you with the principle of least privilege.


Provide New Users With Minimal Access

The first step towards a least privilege model is to ensure that each employee only receives privileges that are absolutely necessary for their business role. The easiest way to make this process secure and consistent is to automate user provisioning through role-based access control, i.e. defining default privileges for employees in different departments, positions, etc.

RBAC also has the advantage of automatically revoking privileges when a user’s role changes, such as when changing departments. However, it is still up to you to decide which permissions are really necessary for different user groups. Remember to keep baseline access as low as possible. You can still grant additional privileges on a case-by-case basis later.


Audit Existing Privileges

If you’re new to the principle of least privilege, chances are accounts in your network currently have a lot of access rights they don’t need. You have two ways of dealing with this problem: either removing all privileges and starting fresh or combing through accounts to audit and delete unnecessary permissions. Which way is the right one depends on how many users you need to deal with and how complicated it would be to re-provisiong them from scratch.

One thing is certain, however: To maintain least privilege access long-term, you need a tool for permission reporting that allows you to identify and correct unintended and potentially problematic access.


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Document New Permissions

Sometimes, users need additional permissions to take on new tasks. The least privilege model shouldn’t stop you from providing employees with the privileges and assets they need to do their jobs. What’s important however, is to keep track of any permissions you grant to make sure they are removed once no longer needed.

Again, the easiest way to support proper documentation is through an automated platform. For example, tenfold‘s self-service interface allows users to request additional permissions, which are then approved or denied by data owners within the corresponding department (freeing up your IT admins for more important tasks). Behind the scenes, tenfold documents every step of this process and automatically adds the new permission to the next audit.


Use Temporary Access Whenever Possible

Some apps allow you to define an expiry date when you grant access to another user. For example, when inviting another person to collaborate through Teams, OneDrive or SharePoint, you can set a date when their file link expires. The advantage of this approach should be obvious: When access rights expire on their own, you don’t have to remember to remove them.

Unless a team member genuinely needs permanent access, you should use the temporary access feature whenever you can. Again, IAM tools can add this capability even to services that do not natively support it.


Perform Regular Access Reviews

The only way to be sure that no one in your organization has access to data or systems they do not need is to check. User access reviews, a periodic audit of all access rights within your organization, are an essential component of maintaining least privilege.

Conducting these audits can be a hassle, but is made significantly easier by a platform like tenfold, which automatically notifies data owners, compiles pending audits into handy checklists and documents the results for later review or compliance verifications.

Least Privilege Checklist

  • Pay special attention to privileged accounts and follow security best practices. A privileged access management (PAM) solution may help you lock down admin accounts.

  • Make sure admins use two separate accounts: a regular account for day-to-day operations and an admin account only used when tasks require it.

  • Don’t forget about account security even if you follow least privilege. Secure accounts using multi-factor authentication and one-time passwords.

  • Users that cannot access a folder can still learn sensitive information from its name alone. Access based enumeration allows you to hide directories from users who cannot open them.

  • Keep an eye out for employees using shadow IT. The best security policy becomes ineffective when staff circumvents it through unsanctioned tech.

  • Implement just-in-time access to provide your users with temporary privileges to complete specific tasks.

Least Privilege Made Easy With tenfold

As you can see, implementing and maintaining the principle of least privilege is a complex task that all but requires a dedicated access management solution. Unless you plan to personally review hundreds of local and cloud accounts for compliance, month after month, you need an IAM software that lets you automate user provisioning, audit privileges regularly and track permissions across all systems.

tenfold does all this and more. But that’s not what makes our IAM solution so special. No, the truly revolutionary thing about tenfold is just how easy it is to set up and use our platform. Our standardized plugins allow you to connect Windows and Microsoft Cloud services as well as third-party applications in a few simple steps: no coding or scripting required. This way, tenfold is ready to use in just a few weeks, a fraction of the time it would take to set up a comparable IAM system.

Learn more about tenfold‘s powerful and intuitive IAM platform by watching our demo video or request a free trial to explore our software to your heart’s content.

Least Privilege RequirementSolution in tenfold
Revoke access once no longer neededtenfold automatically compares users’ privileges to the roles defined by the organization. When an employee’s role changes, tenfold adjusts their permissions as necessary.
Set expiration dates for additional privilegesTo provide users with limited-time access, tenfold allows you to add expiration dates to any privileges requested through the self-service platform.
Document all changes to permissionstenfold ensures that all changes to permissions, from automated workflows to manual requests and changes, are fully documented for review and audit purposes.
Audit permissions regularlytenfold makes permission reviews easy by notifying data owners and compiling audits into clear checklists. You can choose the review interval yourself, including the option to audit critical systems more frequently.
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About the Author: Joe Köller

Joe Köller is tenfold’s Content Manager and responsible for the IAM Blog, where he dives deep into topics like compliance, cybersecurity and digital identities. From security regulations to IT best practices, his goal is to make challenging subjects approachable for the average reader. Before joining tenfold, Joe covered games and digital media for many years.