by Cecil Dildine

The principle of least privilege (POLP) is a base concept of the Zero Trust (ZT) security model. It operates on the premise of "never trust, always verify."

Did you know that "trust but verify" is an old Russian proverb that President Ronald Reagan quoted several times in the context of nuclear disarmament discussions with the Soviet Union? It communicates the need to consistently validate what we are being told in policy and reports through enforcement, auditing, and inspection.

POLP limits user access to only that information absolutely needed to perform job functions.

Relative to ZT, POLP limits user access to only that information absolutely needed to perform job functions. It thus helps reduce the potential harms from unauthorized access. ZT-secured systems rely on POLP controls in scenarios where they are: evaluating access requests to determine whether to grant access; ensuring access is limited to the "need to know" specific data; and assessing whether the device in use is authorized to enter a network and/or connect to a database.

Multiple processes and technologies perform these functions. They can grant individuals permission to read, write, or execute only the files or resources necessary to accomplish their mission. They also can enable time-limited privileges that restrict user access to critical data for only the specific amount of time needed to perform tasks.

Without POLP controls, an organization could create overprivileged (super) users, increasing the chance of data breaches and malicious/nefarious acts resulting in data loss, financial impacts, and even more dire consequences. Consider that the average cost of a data breach was $4.88 million globally in 2024, according to IBM’s latest Cost of a Data Breach Report 2024. In the United States, it was nearly double that, at $9.36 million.

Without POLP controls, an organization could create overprivileged (super) users, increasing the chance of data breaches and malicious/nefarious acts resulting in data loss, financial impacts, and even more dire consequences.

A multitude of tactics can help reduce an organization’s attack surface, including micro-segmentation, system hardening, complexity elimination, and more. However, all efforts must begin with users, and they must focus on critical data.

It is time to define what minimal access to systems, services, and data users require—then provide only that.

As we approach the DoD’s 2027 ZT Target Requirements, it is time to define what minimal access to systems, services, and data users require—then provide only that. Denying access today will not only begin bringing your organization into compliance but also place your team on a better path toward a secure future.

REFERENCES

U.S. Department of Defense Office | DoD Zero Trust Strategy
https://dodcio.defense.gov/Portals/0/Documents/Library/DoD-ZTStrategy.pdf

IBM | Cost of Data Breach Report 2024
https://www.ibm.com/reports/data-breach