Using the Principle of Least Privilege for Maximum Security

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Developer Advocate

Security professionals regard the principle of least privilege highly because enforcing this principle reduces the risk of all security issues. This principle reflects a fundamental idea of zero-trust security design: assume that attackers will eventually breach any system, therefore, build the system to contain the breach. Implementing least privilege administrative models is imperative for an organization wishing to protect its SDLC in the event of a compromise and is a crucial component of compliance standards, including SOC 2 Type II, PCI-DSS, ISO 27001, Fed RAMP, and more.

Least privilege principles adhere to the idea that any user, program, or process should have only the bare minimum privileges necessary to perform its function. Allocating minimal permissions is recommended because, in cases where a user account is compromised, excess privileges expose more attack surfaces.

Furthermore, in DevOps and CI/CD environments, lateral movement across the SDLC is becoming easier as tools become more automated and interconnected. Hence, it is even more critical not to expose excess privileges that could inadvertently unlock additional unintended access in these environments. Following the principle of least privilege is a foundational element of effective application security.

The least privilege concept is simple, so why doesn’t every organization enforce it?

First, extraneous privileges may facilitate productivity, should the user ever need them. Over-prescribing the least privilege undermines a user’s ability to perform their job, and adding privileges typically (and rightly so) has layers of approvals that take time.

Second, as the software development life cycle evolves, the software supply chain becomes more complex. More teams and more tools increase the number of privileges and user profiles that security teams need to manage. Yet, most organizations have no way to centralize governance and security policies across tools and phases of the SDLC.

Benefits of Implementing the Principle of Least Privilege

Implementing the least privilege brings about several key benefits that serve the ultimate goal of hardening an organization’s security posture:

  • Minimized attack surface
  • Limited malware propagation and reduced blast radius
  • Better system stability, due to restricted effect of changes 
  • Improved audit readiness & proactive compliance  

Organizations may realize these benefits by carefully considering best practices early in the SDLC. Adopting best practices is easier said than done, so we present our recommendations for effectively implementing the principle of least privilege.

How to Implement the Principle of Least Privilege

We prescribe the following actions within your organization’s development and deployment ecosystem to implement the least privilege.

1. Audit Permissions Regularly

Auditing for excess privileges helps improve application security throughout the SDLC. Behavior-based auditing tools are imperative to lockdown permissions. Cases illustrating this include:

  • users with admin privileges that do not use admin features
  • users with write access that never make changes
  • users with access to repositories that they don’t view

Detecting and reacting to this behavior is vital in an effective permissions audit.

Identifying stale credentials, extraneous users, unused dependencies, and other points of ingress within the SDLC helps identify potential attack vectors. Check that all privileged accounts, processes, and programs only have the required permissions to perform their required tasks effectively.

2. Default Accounts with Least Privilege

The permissions granted for each created account should be minimal. The best strategy for managing privileges involves only presenting specific functions as required to perform the necessary duties of a job. 

3. Enforce Separation of Duties

Enforcing the separation of duties helps achieve the larger goal of implementing the principle of least privilege. This includes:

  • Separating admin accounts from standard accounts.
  • Compartmentalizing higher level and lower level system functions. 
  • Executing regular tasks with lower privileges than those available to less frequent administrative tasks.
  • Requiring multiple conditions to grant permissions.

A system should check the state of multiple conditions before granting permissions to an object. Checking access controls on only one condition may not be adequate for solid information security; requiring various checks for access can potentially prevent an attacker from launching a successful attack.

4. Utilize Just-In-Time Privileges

User accounts may need to make one-off changes that require root access. The best way to grant these temporary privilege escalation is through single-use credentials generated at the blessing of a trusted superuser described in SLSA Common Requirements or from a password vault. 

This type of activity should be rare, logged, and gated behind multi-party approval. Such sensitive changes should also have high visibility. Moreover, Just-in-Time privilege strategies are best deployed with critical code monitoring to ensure that even temporary privilege escalations are not abused on the most sensitive assets involved.

5. Detect Hardcoded Secrets

Protecting authentication secrets from exposure helps prevent the abuse of these secrets. Teams should take special care to adhere to the least privilege when handling secrets–credentials including developer credentials are sought after because of the access they provide.

Hardcoded secrets undermine least privilege because they give anyone with access to the secret additional privileges. Furthermore, a common misconception is that secrets are only found in source code repositories. Hardcoded Secrets can be found throughout the SDLC in Infrastructure-as-Code, logs, containers, and the production environments.

Recklessness with secrets is an anti-example of the principle of least privilege. Therefore, organizations should enhance the security of processes in place for handling secrets. A maturity model for secrets provides a framework for ensuring that credentials and other secrets are securely stored and used. 

6. Audit IaC Configurations

IaC misconfigurations are frequently the cause of cloud security breaches. AWS S3 misconfigurations alone account for 16% of cloud security breaches. Many of these breaches are caused by a public access configuration that should’ve been set to private. 

The nature of cloud infrastructure entails elastic scaling capabilities. While this is great for productivity, automatic provisioning propagates mistakes and vulnerabilities as infrastructure is scaled in deployment environments.

7. Log Individual Actions

Making individual actions traceable improves the trackability of changes. Logging access by user ID and generation of one-time passwords plus monitoring and automatic auditing enhances the visibility of potentially compromising activities. This automated auditing helps aid governance by escalating when violations to set policies are identified–this would not be possible without logging actions.

Logging also exists as a compliance requirement. ISO 27001, PCI DSS, NERC, and HIPAA contain logging requirements related to configuration changes and user access. Adhering to these many requirements is difficult to enforce across all assets, but utilizing asset inventory tools to help your organization perform compliance audits helps ensure sufficient logging and prevents coverage gaps.

8. Automate privilege remediation

Reacting quickly to excessive permissions can help thwart potential attacks, minimize code leak time, and prevent potential compliance violations. The quickest option for remediating excessive privileges is through automated remediation. Much like auditing for excess privileges is far easier to achieve from a centralized platform than via each team, tool or phase of development, centralized platforms can also help automate and centralize remediation by pushing privilege updates into target systems.

Automatic privilege remediation also looks like proactive action to prevent stale credentials from posing a threat. Organizations may achieve this through automatic key rotation, which replaces sensitive keys and secrets.

Enforcing Least Privilege with Cycode

Cycode’s platform offers a suite of capabilities that help organizations enforce the principle of least privilege across the SDLC. This includes source, container registries, IaC configurations, cloud, and more.

Beyond enforcing the least privilege, Cycode provides complete visibility into enterprise DevOps tools and infrastructure. Cycode’s capabilities include comprehensive security scanning and preventing escaped secrets, environmental drift, code leaks, and other common issues, all within flexible developer-friendly workflows. Furthermore, Cycode helps apply security best practices for IaC code when using Terraform, Kubernetes, YAML, ARM, and CloudFormation.

Cycode included workflows that can help ensure adherence to least privilege principles. As described in my prior blog post, workflows can be used to send alerts, create tickets, and automatically remediate cases where the configurations violate the principle of least privilege. For example, workflows may prescribe remediating action when Cycode detects stale admin privileges within a repository.

Learn More About Implementing Least Privilege

Schedule a demo or visit our website to learn how Cycode can help secure your software supply chains.

Originally published: March 10, 2022