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Least Privilege

The principle of least privilege is a foundational security guideline that limits user access to only the resources required to perform their role. Restricting unnecessary permissions reduces attack surface, limits malware propagation, and minimizes the impact of security incidents.

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About this video

The principle of least privilege is one of the most fundamental governing principles in organizational security, holding that any user, account, or system should have access only to the specific resources required to carry out its intended function — nothing more. Although it is closely associated with identity and account management, the principle applies broadly across personnel, software, services, equipment, and data, making it a baseline standard for security decision-making throughout an organization. When access permissions exceed actual need, the consequences of a security incident scale accordingly, turning what might be a contained problem into a significant business disruption. A practical example illustrates why this matters: a trusted, security-conscious employee with access to all departmental shared drives becomes a serious liability if her machine is infected with ransomware, because the malware can encrypt every resource she has permission to reach. Had her access been limited to only the drives she genuinely needed, the same incident would affect a much smaller portion of the organization's data, reducing both recovery time and operational impact. Consistently applying least privilege keeps the attack surface small, slows or stops malware propagation, and protects against the unpredictable consequences of human error — making it an essential practice for any organization serious about security posture.

What you'll learn

Explain the principle of least privilege and its role in reducing attack surface, limiting malware propagation, and minimizing the impact of security incidents

What's covered

Principle of Least Privilege

Definition & Scope
- Foundational governing principle
- Applies beyond personnel
- Identity & account management
Scenario: Employee Bev
- Access to all shared drives
- Ransomware compromises system
- All drives encrypted
- Less access reduces impact
Advantages of Least Privilege
- Reduces attack surface
- Limits malware propagation
- Safeguards against human error
- Improves performance
Where to Apply
- Equipment & software
- Services & data

Aligned to

NIST 800-53

AC-6 Least Privilege

NIST CSF

PR.AA-05 Access permissions, entitlements, and authorizations are defined in a policy, managed, enforced, and reviewed, and incorporate the principles of least privilege and separation of duties.

CompTIA Security+

4.6 Given a scenario, implement and maintain identity and access management.

ISC2 CISSP

5.4 Implement and manage authorization mechanisms

Key terms

Least Privilege: A security principle that grants users and systems only the minimum access rights needed to perform their functions.
Attack Surface: The total set of points in a system where an unauthorized user can attempt to enter or extract data.
Malware: Software specifically designed to disrupt, damage, or gain unauthorized access to a system.
Ransomware: A type of malware that encrypts a victim's files and demands payment in exchange for the decryption key.
Privilege Escalation: An attack that exploits vulnerabilities to gain higher-level access than originally authorized.

Topics

Least Privilege Access Control Identity And Access Management Attack Surface Cybersecurity Malware Defense

Transcript

There might be some foundational policies, some governing principles, that we use to govern everything that we do within the company. One of those that's really common, and that we should be doing, is least privilege. It's one of the most basic levels when it comes to these governing principles.

One of the things that you may hear this called is principle of least privilege. This is a guiding principle that we use for a lot of our security measures. This doesn't apply just to personnel management; it really applies in a lot of other areas, specifically identity and account management. But I do think it's one of those principles we should use throughout the company, and certainly when it comes to personnel management.

A scenario

Let's start out with a little scenario so we can talk about least privilege, what it is, and an example of why it's really necessary.

Let's say we have an employee, Bev. Bev is in charge of a lot of different things and she's very high up in the company. She's a very trustworthy person, and also she's very security conscious. Because of this, and because of her need in this company, she has access to a lot of shared resources. These are all shared drives, shared network drives, and they're for all of the different departments within the company. She doesn't necessarily need access to everything, but occasionally it's nice for her to have access to things so she can keep tabs on everything that's happening within the company.

Let's say, not a problem that she really specifically had, but just her computer got compromised for some reason. It was completely innocent, and she, like I say, is very security conscious. But what happened is it was ransomware, and it encrypted all of these drives so that people didn't have access to these drives. Now this is really problematic. This is going to be very disruptive to the business. Hopefully we've got a backup and can restore these, but either way it's going to be disruptive for the time we have until we do a full restore of this information.

So here we've done what we consider everything right, and we still have a big problem here.

Now just imagine if she had access to less stuff, the folders that she really didn't need to have access to, that she didn't have access to to begin with. So maybe it's these folders right here. Maybe there's a few that she still needs access to, but maybe half of these she didn't need to have access to. Now the same scenario becomes less disruptive and less of a concern, and maybe we can recover much faster because we have much less data that we need to restore.

So in just this simple scenario, practicing least privilege, where Bev has the least privilege to the least amount of resources, really saved us a lot of time and headache.

Advantages, and where to apply it

The advantages of least privilege, giving people the least amount of access that we possibly can:

It reduces the attack surface.
It reduces malware propagation, things like ransomware.
It improves performance.
It safeguards against human error.

So really, what we want to do in these scenarios is practice least privilege. So where might we use this? Well, we want to use this on equipment, software, services and data. Pretty much anything we have access to, we want to practice least privilege.

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