Principle Of Least Privilege

Least privilege is a cyber security principle that is used to enhance protections by minimizing access to systems and data by users, applications, or services. Also referred to as the principle of minimal privilege or the principle of least authority, the principle of least privilege provides access based on the need to perform a legitimate function.

The objective is to prevent over-privileged access that increases the risk of credential exploitation if they are compromised. 

From a systems perspective, the principle of least privilege means each part only has the privileges that are needed for its function. For instance, a backup system only has the ability to perform those specific tasks and is blocked from changing data or installing software.

By partitioning functions, even if a cyber-attacker gains access to one functional area, they are unable to expand into the rest of the system.

Effective management of least privilege requires implementing access controls without negatively impacting productivity. The objective is to fully enable operations, but to minimize the potential attack surface by having users’ accounts, applications, and services running with as few privileges as possible to complete a specific task or job.

Implementing Least Privilege

The following are several fundamental considerations when implementing least privilege.

• Identify all assigned privileges
  An important first step for implementing least privilege is understanding what administrative privileges are in use, including those inherited via group memberships.
  
  In addition, an inventory should be made to identify what employees, devices, software, services, applications, and hardware have which access privileges.  
  
• Monitor privileges and learn the usage
  Before enforcing restrictions or least privilege, a usage baseline should be established to determine what is normal behavior. This will help ensure that the right access is available and help identify over-privileged accounts.  
  
• Assign users with access privileges based on need
  Update users’ access privileges to minimize privileges based on the requirements of the tasks or jobs. And, create policies to adhere  to least privilege when assigning future user access.
  
• Embed least privilege into system configurations
  Minimize privileges for non-human accounts, such as applications, systems, or devices (e.g., automated backup systems, IoT devices), to limit functionality to specified tasks.
  
  Often, documentation directs that users be given a higher level of administrative access even when lesser permissions are all that is necessary. Documentation should be carefully reviewed to determine the least privilege that is required.
  
  Applications, systems, and devices should be locked down by changing default passwords and disabling any default accounts and services that are not part of the system’s approved functions. Applying least privilege prevents them from becoming jumping off points for potential attacks.
  
• Perform periodic access reviews
  Confirm that the principle of least privilege is adhered to by regularly performing audits to assess usage, privilege levels, and changes. Three recommended least privilege audits are:

1. Change audits are used to identify unauthorized or suspicious changes to an account’s password, permissions, or settings.

2. Usage audits review what each account is doing, including what data is accessed, created, and deleted.

3. Privilege audits determine whether users have the correct privileges. This is meant to address the issue of users accruing privileges that are not needed. This most commonly happens when:

• Job roles change
• When new privileges are added to the old ones
• When users are given extended access for a specific project and the privileges are not adjusted when the temporary project is completed

• Segment admin accounts
  Create separate accounts for administrators who require elevated privileges to perform IT management functions. For instance, have administrators use accounts with minimal privileges for basic functions (e.g., accessing email, internet access) and provide accounts with elevated privileges to use when performing tasks that require broader access privileges.  
  
• Delete accounts
  An obvious but often-overlooked application of least privilege is simply deleting accounts. When a user no longer needs an account (e.g., change in job, s/he is no longer with the organization), the account should be immediately disabled so that any data and logs can be pulled.
  
  Then, once it has been verified that the account is no longer needed, it should be deleted to avoid having it be used as a potential attack vector.  
  
• Manage privileges
  • Set up groups
    Create groups with different sets of privileges and assign users to groups based on their job roles. If a user’s tasks or responsibilities change, they can be removed from a group and transferred to a different group rather than by manually adding or removing privileges, which is time-consuming and error-prone.
  • Assign users working hours
    Another layer of least privilege is restricting account access to assigned hours when a user normally works
  • Use location-based restrictions
    Limiting the locations from which an account can be used is another way to apply least privilege.   
    
• Restrict use of machines
  Machine-based restrictions are a type of least privilege control that prevents unauthorized use of IT equipment.

Similar Principles

The concept of restricting access can be accomplished with other principles, several of which work in concert with least privilege.

• Defense in Depth

Defense in Depth (DiD) uses multiple layers of security to provide fail-over defense mechanisms to protect critical data. An example of defense in depth would be the combination of anti-spam and antivirus software, web application firewalls (WAFs), privacy controls, and user training for website protection. Another would be network security that combines firewalls, , and intrusion prevention systems.  

• Fail Safely Failure Stance
  The failure stance, or the state in which a device is left if it fails, should be configured to fail safely. If systems should fail, they should be programmed so that they deny access to a cyber-attacker.  

• Business Need to Know 

The business need-to-know security principle refers to having a justification or reason for a group of individuals to access data for a specific purpose, as compared to least privilege, which applies to users’ rights and permissions.

For example, if a user is recognized as having a legitimate need to access financial data, a need-to-know policy will determine what kind of access should be granted (e.g., read-only, update, delete). 

• Zero Trust

The principle of zero trust is based on the assumption that any user or system that wants to access a network, services, applications, data, or systems must earn trust through verification before gaining authorized access. Identification and verification are based on various security controls, with additional layers added for more sensitive resources.

Examples of these security controls are password authentication protocols (PAP), authentication tokens, symmetric-key authentication, and biometric authentication, with experts strongly recommending using multi-factor authentication.

Examples of Least Privilege

IT Administrators
For organizations with administrators who focus on different IT areas, least privilege should be applied to restrict access to functional areas. For instance, the administrator that is responsible for deployment and management of the organization’s Windows servers should not have equivalent access to its email servers. Applying least privilege reduces risk by partitioning access. If one of the administrators’ credentials are compromised, the risk is limited.  

Applications
Some software applications have a legitimate need to modify particular files and folders. However, without applying the principle of least privilege, the application could run under a service account that has administrative rights to the organization’s application servers.

In this case, if the application is compromised, the damage could be significant. With least privilege, the service account would only be granted read, write, or update access for the specific files and folders the application needs to modify.

Connected Third-Parties

Many organizations have use cases where third parties are granted access to systems and networks (e.g., remote HVAC management). Least privilege ensures that these users’ access is strictly limited. However, if third parties are over-privileged, seemingly benign access can become a security risk by allowing cybercriminals to use third-parties’ authorized access as a starting point for cyber-attacks or theft.

Help Desk Staff 

To support users, help desk staff usually need super-admin access levels. However, near-unlimited access presents a major security risk and can result in a significant security breach. While help desk teams often require elevated privileges to do their jobs, least privilege controls can be implemented to reduce risk. 
This can be done by granting help desk staff standard access privileges, but providing a mechanism to escalate privileges as needed to address specific issues. This restricts unauthorized access in the event that a help desk staff member’s credentials are stolen, and reduces the risk of insider threats.

Alternatively, programs and processes that would require admin privileges can be set up to be read-only. This means that authorized scripts needed to perform upgrades, configuration changes, or patches could be run by not modified. 

Avoiding Privilege Creep

Least privilege security protocols help curb privilege creep, which is when users gradually accrue unneeded permissions, access rights, and privileges. The two primary drivers of privilege creep are when IT teams fail to remove old user privileges, or users are overprivileged by their managers. Privilege creep leads to a number of security issues, including increasing the risk of a breach.

Six Suggested Steps To Avoid Privilege Creep

1. Access control policy
Establish the security requirements for access, including access authorization, administration, and audit functions.

2. Governance and least privilege administration
Create rules for authorizing access, implement processes to regularly audit users’ access and modify access privileges as needed to ensure that users only have access to what they need.

3. Limitations on user access management
Minimize the number of people who manage users’ access, giving greater control over access and applying least privilege to IT.

4. Provisioning and de-provisioning protocols
Implement procedures, with the support of the security team, for provisioning and deprovisioning users’ privileges.

5. Auditing and certification
Routinely check users’ access privileges against their needs and either de-provision those that are not required or certify that users’ access meets least privilege standards. 

6. Access control tools
Manage access strategically, replacing passwords and other outdated authentication methods with intelligent identity management tools and multi-factor authentication methods to effectively manage access according to least privilege principles.

Benefits of Least Privilege

Incorporating the principle of least privilege into cyber security programs yields many benefits for organizations. Those that can effectively set up and enforce least privilege see a material decrease in risk. Among the many other benefits realized when least privilege is embedded into cyber security are the following.

• A strategic balance of control and access 
• Adherence to compliance requirements for data protection
• Enhanced security that limits exposure to cybercriminals and malicious insiders  
• Increased user satisfaction by providing access to the resources they need  
• Mitigation of the risks and errors caused by cyber fatigue
• Reduced costs to manage users’ access securely 
• Reduction of cyber security burden of responsibility on employees
• Access and controls are limited to what users need to do their job—and nothing more

Additional benefits of embracing the principles of least privilege are outlined below.

• Compliance management
  Using least privilege helps organizations meet strict industry, government, and internal compliance requirements for restricting administrator access and providing data protection.
  
• Malware risk mitigation
  By limiting what can be accessed with users’ credentials, least privilege minimizes the risk posed by malware, especially ransomware. Least privilege can keep malicious code isolated on a single workstation rather than allowing privileges to be exploited, which can enable the malware to spread across the network to other systems. 
  
• Control third-party vendor’s access
  Least privilege ensures that outside service providers have the access they require, but limits an organization’s exposure in the event that credentials are compromised. 
  
• Minimize an organization’s potential attack surface
  Least privilege limits what can be accessed and what can be done if a user’s credentials are stolen. Even if a cybercriminal gains access to a user’s credentials, the scope of damage can be materially reduced with least privilege controls in place. 
  
• Improved system stability
  In addition to cyberattack prevention, least privilege restricts users’ access to systems, thereby protecting them from human errors, which can result in enhanced system and network stability.

Enhanced Security Posture with Least Privilege

According to experts, there is no question that least privilege delivers superlative value and protection. As with all security systems, care must be taken to implement least privilege in a way that is manageable and does not impinge on productivity. Effective execution of the principles of least privilege comes down to process and oversight.

Systems need to be implemented to support access management—by granting and retracting privileges along with escalating and de-escalating access based on users’ needs. Special care needs to be taken with third parties, who deliver important services, but can also represent a tremendous liability. Just as with inside users, third parties’ access needs to be commensurate with their needs.

By embracing the principle of least privilege, organizations significantly enhance their security posture by reducing risk and potential attack surface. With least privilege, if credentials are compromised, the limitations on access mitigate the damage that can be done by a cyber attack.

Be proactive and assess the state of your security profile to identify the gaps. Find a solution that addresses deficiencies in a way that does not overburden your IT staff or require workflow changes from other team members.

Egnyte has experts ready to answer your questions. For more than a decade, Egnyte has helped more than 16,000 customers with millions of customers worldwide.

Last Updated: 8th July, 2022

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