Least Privilege Access: How to Keep Sensitive Data on a Need-to-Know Basis

Least privilege access ensures that users do not accumulate unnecessary permissions, which can become a security risk if your network is breached or data is stolen. In this article, we will examine the advantages of the principle of least privilege, the risks organizations face due to excess privileges and explain how you can implement least privilege access in your network.

The principle of least privilege is a cybersecurity concept designed to help protect sensitive data by limiting who can view, use and edit information. The basic premise is to look at every access right as a potential risk: While your staff needs certain permissions in order to do their jobs, these same rights can become a threat to cybersecurity when used with malicious intent.

For example, your business could be facing an insider threat in the form of a disgruntled employee who decides to commit data theft. Or maybe an intruder manages to hijack an account on your network using phishing, leaked credentials or similar means. The more systems a user can access, the more business data is now at risk.

The easiest way to stop access rights from being exploited is to simply delete them. And that’s what the principle of least privilege is all about: Removing unnecessary permissions until every user only holds the minimum level of access that is absolutely required in order to do their job.

The principle of least privilege is a key part of zero trust architecture. The two concepts are closely related, since both approach cybersecurity by examining the worst case scenario and taking every precaution to avoid this outcome and limit the potential damage. But while zero trust deals with authentication and authorization within the local network, least privilege is about limiting access as much as possible from an organizational perspective.

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

The principle of least privilege is often used synonymously with the term need-to-know. In fact, there is significant overlap between both concepts. Just like the least privilege principle, a need-to-know basis aims to limit access to critical data to as few people as possible.

The difference is in the scope of the two terms: While need-to-know is concerned with the number of people who can view certain information, the principle of least privilege also covers non-human users such as system accounts, applications, services and devices.

Under POLP, users are granted only the exact privileges they need to perform their duties. The easiest way to ensure permissions are assigned correctly across your entire company is to automate the process using role-based access control and an identity & access management solution. In companies that do not implement IAM systems, admins must manually assign and update all of these privileges.

This may not seem like a big deal at first. When a new hire joins your staff, assigning them the basic permissions needed for their job is not that complicated – though many companies mess up at this stage by copying a reference user and transferring more privileges than intended. The real trouble, however, comes when it’s time to update or revoke these permissions.

In most organizations, users constantly need new and different privileges, for all sorts of reasons: They change departments or are assigned to new projects, requiring new IT permissions. They might go on parental leave and need to have their access temporarily revoked. The list goes on. Except nobody remembers to keep an actual list. Admins update privileges when a request comes in, but remembering every change and tracking when extra privileges are no longer needed? It’s next to impossible.

This is where manual access management runs into its biggest problem: Nobody remembers to revoke permissions once a project is finished or users return from a temporary assignment. And how could they! Even in smaller organizations, admins would have to keep track of hundreds and thousands of permissions across various systems and applications.

Over time, users end up with more and more permissions they no longer need. This gradual accumulation is also known as privilege creep or privilege sprawl. Access rights from previous roles and old projects, temporary permissions that end up being permanent, privileges that are easy to forget about. Until they become a problem. Take the Colonial Pipeline Hack, for example, where cybercriminals gained access to the company network through a VPN account that was no longer in use.

POLP is an important factor in endpoint security, which ensures that malware such as trojans or keyloggers cannot spread freely through your system. Malware can infiltrate your system through various attack vectors, such as phishing emails, zero-day exploits or application vulnerabilities that allow for remote code execution. Once inside, malware relies on lateral movement to jump from device to device and infect your entire network.

By reducing user privileges down to the absolute minimum, you can also limit the movement options for viruses and ransomware. Privileged accounts, such as administrator and superuser accounts (e.g. databases, networks, and system admins), are of particular significance in this context because cyberattacks nowadays tend to be geared toward exploiting privileged credentials. Aside from relying on POLP, software solutions for Privileged Access Management (PAM) offer additional tools and services for safeguarding administrator accounts.

Employees can only steal data they have access to – that goes without saying. But one major risk that is often overlooked comes in the form of special rights, for instance remote access for staff working from home. Obviously, as an employer, you want to trust your employees and don’t expect them to abuse their privileges.

However, if you do permit them to work from home using a VPN connection, you’ll still want to make sure that you have the DLP function (data loss prevention) in the VPN software activated. Just in case! To learn what could happen if you choose to ignore this important security measure, read our post about Jerry and the forgotten VPN connection.

Another lurking danger that can be countered using the least privilege principle is that of former employees abusing access rights that haven’t been revoked. If POLP is implemented correctly and consistently, these privileges are removed as soon as a staff member leaves your organization.

In organizations that have not yet implemented an Identity and Access Management solution, admins sometimes grant admin privileges to non-admin users.

The idea behind this is to give senior staff, such as department heads, the rights needed to assign privileges themselves without having to go through the IT department every time. It is a total time-saver because it frees up time for IT admins, allowing them to focus on more important matters. Right?

What if your company is suddenly facing a compliance audit and you have to manually prepare a report on access to sensitive data. Yikes. That’s not just going to keep your IT staff busy for weeks on end, but many other people including, quite likely, your boss. And your boss’s boss, too. That’s a pretty expensive Christmas light.

Every company must ensure that both internal and external compliance requirements are met. Requirements from regulations such as the GDPR, the SOX Act and HIPAA or security standards like ISO 27001. These regulations (and many others) all require or strongly recommend limiting IT access to what is strictly necessary. The exact language may differ, but in essence all these norms expect you to follow the principle of least privilege.

To establish the principle of least privilege in your company, you must first declutter your current access structure and identify the weakest links in your network. Here is a list of measures you must take to accomplish this:

Once you have tidied up your access landscape, you must ensure the principle of least privilege will be applied rigorously at all times going forward. In organizations with only a few employees, this can usually be achieved manually if admins work precisely and always follow policy. Still, this approach leaves you open to human error.

But even if your company does not have thousands of users, automating processes might still be a goal worth pursuing. For example, this can help you save time if the internal processes in your organization are very complex and require a more diverse and flexible access structure. Whether it is the number of users or complexity of your environment that applies, or both – investing in an access management or identity and access management software is probably a good idea.

There are many options and tools that can help you implement POLP and achieve a high degree of data security. The question is how much time you are willing and/or capable of investing into the manual efforts required and whether you believe the operational discipline needed for the implementation is strong enough in your company.

Not only does the access management software tenfold assign permissions to users automatically and in accordance with POLP, it also cleans up your organization’s access structure.

tenfold builds your access structure automatically according to the principle of least privilege. How does it do this? First, tenfold’s profile wizard analyzes which privileges should be included in the standard privilege set for each department. Once this is done, the software assigns the specified standard rights to users automatically and for all connected systems (including Active Directory and SAP).

One of the key differences between the software and a manual management of access rights is that the software will also automatically take care of obsolete privileges. For instance: if a user changes to a different department, the software will automatically revoke that user’s old privileges and assign the necessary new privileges. If a user leaves the organization, tenfold automatically deletes all associated accounts and privileges, preventing ex-employees from sneaking into your network.

Recommended action	Solution in tenfold
Remove all outdated and/or superfluous privileges	Once an access profile has been defined, tenfold compares the data set with current access structures to determine which privileges do not match the profile. The software then automatically removes any privileges that divert from the profile specifications.
Implement Just-In-Time access	In tenfold, users can request access rights via self-service and data owners can respond to such requests by approving or declining them. It is not possible to request or approve privileges “just in case they might be needed“.
Fixed expiry dates for extra privileges	tenfold is able to model the workflow for privileges that are granted on top of a department’s standard set and which require an expiry date due to security reasons. Data owners can always push back such expiry dates if necessary.
Seamless documentation of all activities related to admin accounts	tenfold ensures that ALL processes and activities are seamlessly documented and produces audit-proof reports with just one click.
Require data owners to review privileges regularly	tenfold allows you to automate user access reviews thanks to regular reminders sent to the relevant data owners at the interval of your choice.