Improper Separation of User/Administrator Privilege in Cybersecurity
This article is part of a series where we look at a recent NSA/CISA Joint Cybersecurity Advisory on the top cybersecurity issues identified during red/blue team exercises operated by these organizations. In this article, you will find a more in-depth look at the specific issue, with real-world scenarios where it is applicable, as well as mitigation strategies that can be adopted to limit or overcome it. This expands on the information provided by the NSA/CISA report.
The separation of user and administrator privileges is a cornerstone of robust cybersecurity practices. However, improper management of these privileges can lead to severe security vulnerabilities. This chapter delves into the nuances of this issue and outlines effective strategies to mitigate associated risks.
Issues in Privilege Separation
Excessive Account Privileges
Overly permissive privileges can allow users to access sensitive data or perform actions beyond their role’s scope, significantly increasing the organization’s risk exposure and attack surface. Examples include employees having access to financial records or system settings irrelevant to their job functions.
Elevated Service Account Permissions
Service accounts, often necessary for applications and processes, are granted elevated privileges. These accounts become prime targets for attackers due to their broad access within a domain. For instance, a compromised service account in a database can lead to data breaches or unauthorized data manipulation.
Non-Essential Use of Elevated Accounts
Using administrative accounts for routine, non-administrative tasks, such as email access or web browsing, unnecessarily expands the attack surface. It creates opportunities for attackers to exploit these accounts for network infiltration and rapid compromise.
Accounts Maintaining Privileges after User Departure
Poor account management often results in accounts retaining privileges after they are no longer needed, such as when an employee leaves the company or changes roles. This oversight can leave dormant accounts open to exploitation.
A common consequence of improper privilege separation is system compromise, especially in web hosting environments. For example, if a web server process running Apache/PHP has excessive privileges, any remote exploit providing unwarranted access would inherit these privileges, potentially compromising the entire system. Historical incidents in web hosting platforms demonstrate the severe consequences of such oversights. By lowering the privileges assigned to the web server process, the risk vector would also be reduced.
Limit Administrative Privileges
Minimize the number of administrative roles there are and perform regular reviews of user roles and policies. This practice ensures that only necessary personnel have elevated access, reducing the potential for internal or external exploitation.
When reviewing roles for privilege maintenance (or not), take the default stance of not maintaining them, and then validating why they should have those privileges. If there is no valid reason, then the role should have the related privileges removed.
Implement Time-Based Access
Utilize just-in-time access methods to provide elevated privileges only when necessary, thereby adhering to the principle of least privilege. This approach reduces the time window in which elevated privileges are available, diminishing the risk of their misuse.
Enforce Least Privilege Principle
Regularly audit user accounts to ensure that they possess only the necessary privileges for their roles. This practice minimizes the potential for unauthorized access or actions within the network.
Restrict Non-Essential Use of Elevated Accounts
Prohibit the use of administrative accounts for general tasks. Implementing user behavior analytics (UBA) can help detect and prevent such misuse by monitoring for abnormal activities.
Enforce Strict Account Lifecycle Management
Tightly couple account lifecycles with business requirements. Promptly remove or downgrade accounts when an employee leaves or a contractor’s engagement ends, minimizing the risk of dormant accounts being exploited.
Implement Comprehensive Activity Logging
Enforce strict logging of all privileged activities, ideally across all systems. Use log aggregation tools or monitoring solutions for a holistic view of the infrastructure, aiding in the early detection of unauthorized or anomalous activities.
Effective management of user and administrator privileges is essential in safeguarding an organization’s digital assets. By understanding the complexities of privilege separation and implementing these mitigation strategies, organizations can significantly enhance their cybersecurity posture.