Least Privilege Principle

In this topic, we are going to learn a fundamental aspect of modern cybersecurity and information management. The Least Privilege Principle helps organizations build a strong defense against both external and internal threats, safeguarding data, systems, and networks.

What is POLP?

Least Privilege Principle or POLP for short is a computer security concept and best practice that revolves around restricting access rights and permissions for users, processes, and systems to only the minimum level necessary for them to perform their required tasks. In simpler terms, it means giving individuals or entities only the permissions they absolutely need to do their job. POLP minimizes the potential damage that could result from unauthorized access or misuse.

Significance of the Principle of Least Privilege (POLP)

You might already be aware of one implementation of POLP, whitelist — a specific application of POLP that restricts access or permissions to a predefined and limited set of entities, actions, or resources. Only items present on the whitelist have access, while everything else is denied.

Strategies for implementing POLP

You're probably wondering how you can implement something that follows POLP. Though it seems simple in words, the technical part might be a daunting challenge. Let's look at some possible approaches:

1. User Role-Based Access Control (RBAC): Assign permissions based on specific job roles or functions. Users are only granted access to the resources necessary for their roles.

2. Permission auditing: Regularly review and audit permissions to ensure that they are appropriate and necessary. Remove any unnecessary or excessive permissions.

3. Separation of duties: Divide tasks and responsibilities among different individuals to prevent a single user from having too much power or control.

4. Default deny: Adopt a "default deny" approach, where access is denied by default and only granted when explicitly needed.

One of the most natural ways to implement POLP is to use IDM, which we discuss in the section below.

Identity Management System

IDentity Management (IDM) systems are tools and frameworks that help organizations manage and control user identities, access rights, and authentication processes within their digital systems. These systems play a crucial role in maintaining security, efficiency, and compliance in today's interconnected and complex IT environments. Following the principle of separation of concern, each component (or sub-system) handles a single logical function and depends on other components for operations that are out of scope for the component. An Identity Management System should consist of logical components for the following services:

Components of IDM

Authentication Service — responsible for authenticating users; provides user self-service for password resets, sign-ups, and other services.

Federation Service — responsible for cross-domain Single Sign-on for web applications.

Token Service — responsible for security token issuance and introspection. Primarily for API access and for modern web and mobile application access.

User Management Service — Responsible for user provisioning operations.

Identity Management (IDM) systems play a crucial role in the implementation of POLP by managing user identities, access rights, and authentication. Here are the ways in which IDM systems contribute to POLP implementation and how POLP is implemented within IDM systems:

• User Authentication
• Access Control
• Role-Based Access Control
• Access Request and Approval Workflow
• Deprovisioning
• Monitoring and Auditing
• and more ...

Sounds like there's a lot, but don't worry. Later on, we will briefly look at the implementation of POLP in IDM systems.

Examples of vulnerable applications

Vulnerable applications are often those that grant excessive permissions to users or run with unnecessarily high privileges. For instance, a web application that allows users to upload files but doesn't properly restrict access to those files can become vulnerable to attacks.

But let's consider a real scenario, a Minecraft server. Suppose your boss challenges you to set up a Minecraft server. It might be a Hypixel successor. But to win this battle implementing the Least Privilege Principle is a must because it would involve giving players and server plugins only the permissions necessary to play the game and administer the server while limiting their ability to modify critical system files or perform potentially harmful actions.

For instance, players might have the ability to build structures and interact with the game environment, but they shouldn't have permission to modify server configurations or access sensitive files. On the other hand, server administrators should have elevated permissions to manage and configure the server but would still be restricted from system-level tasks that aren't directly related to running the game.

By applying the Least Privilege Principle in this context, you reduce the risk of players inadvertently or maliciously causing harm to the server or the underlying system.

But what if you don't do that? Who cares about the consequences? By saying this, you potentially expose your server to a range of security and operational risks that result in a waste of money and time. Let's name them:

1. Unauthorized access and griefing: Without proper access controls, players could gain unauthorized access to administrative functions or sensitive areas of the server. This could lead to griefing (deliberate destruction or disruption of the game environment) or unauthorized changes that affect the gameplay experience for others.

2. Data breach: Lack of access controls might result in unauthorized access to player data, including personal information and chat logs. This could lead to privacy breaches and put players' sensitive information at risk.

3. Server instability: Players or plugins with excessive privileges could inadvertently or maliciously modify server settings or configurations. Incorrect modifications lead to server crashes, instability, or degraded performance.

4. Exploits and hacks: Hackers could exploit vulnerabilities in the game or server software, gaining elevated access to the server and potentially compromising its integrity.

5. Malicious plugins: Plugins with unnecessary or excessive permissions could be used to compromise the server's security or even act as a platform for launching attacks against other systems.

6. Lateral movement: In a networked environment, a compromised Minecraft server could be used as a stepping stone for lateral movement within your network, potentially leading to further breaches.

7. Regulatory and legal issues: Depending on your server's user base and location, not implementing proper access controls could lead to violations of data protection laws and regulations.

8. Loss of trust and players: Players may lose trust in the server's security and integrity, leading to a decline in the server's popularity and user base.

Examples of vulnerable POLP configs

Speaking about real life, consider these examples. The following code snippet written in Go fails to enforce proper access controls. Take a look at the vulnerabilities that attackers can exploit.

Direct object references in URLs:

Insecure URL: https://example.com/viewUser?userId=123

Function viewUser:
    userId = getRequestParameter("userId")
    user = getUserFromDatabase(userId)  # No proper access control check
    displayUserInfo(user)

• Vulnerability: Insecure URLs directly expose internal object references, such as database IDs, in the URL.
• Consequences: Attackers can manipulate these references to access unauthorized data or resources. They might view, modify, or delete other users' data.

Privilege escalation via parameter manipulation:

Insecure URL: https://example.com/changeRole?userId=123&role=admin

Function changeRole:
    userId = getRequestParameter("userId")
    role = getRequestParameter("role")
    user = getUserFromDatabase(userId)
    user.Role = role  # No proper authorization check
    updateUserInDatabase(user)

• Vulnerability: Input parameters, such as roles, are not properly validated or authorized, allowing users to easily manipulate them.
• Consequences: Users can elevate their privileges by changing parameters, potentially gaining unauthorized access or control over system resources.

Unprotected sensitive actions:

Insecure URL: https://example.com/deleteAccount?accountId=123

Function deleteAccount:
    accountId = getRequestParameter("accountId")
    account = getAccountFromDatabase(accountId)
    deleteAccountFromDatabase(account)  # No proper authorization check

• Vulnerability: Sensitive actions like account deletion lack proper authorization checks.
• Consequences: Attackers can perform sensitive actions without proper access control. This can lead to data loss, disruption, or unauthorized actions.

Access token leak:

Insecure URL: https://example.com/viewProfile?userId=123&accessToken=xyz

Function viewProfile:
    userId = getRequestParameter("userId")
    accessToken = getRequestParameter("accessToken")
    If accessToken == "xyz" Then  # Insecure token check
        user = getUserFromDatabase(userId)
        # Display user profile

• Vulnerability: Access tokens are exposed directly in URLs or insecurely handled.
• Consequences: Attackers can steal these tokens, gaining unauthorized access to a user's account, personal information, or restricted functionality.

Insecure file downloads:

Insecure URL: https://example.com/downloadFile?fileId=123

Function downloadFile:
    fileId = getRequestParameter("fileId")
    file = getFileFromDatabase(fileId)  # No proper authorization check
    # Provide file download link

• Vulnerability: File downloads do not enforce proper authorization checks.
• Consequences: Users can download files they shouldn't have access to, potentially exposing sensitive information or intellectual property.

Unsecured administrative actions:

Insecure URL: https://example.com/adminPanel?action=deleteUser&userId=123

Function adminPanel:
    action = getRequestParameter("action")
    userId = getRequestParameter("userId")
    If action == "deleteUser" Then
        user = getUserFromDatabase(userId)
        deleteUserFromDatabase(user)  # No proper authorization check

• Vulnerability: Administrative actions lack proper authentication and authorization checks.
• Consequences: Unauthorized users can perform administrative tasks, such as user deletion or system configuration changes which leads to security breaches, data loss, or system instability.

In all these cases, the vulnerabilities can lead to unauthorized access, data breaches, security incidents, and compromised system integrity. To prevent these issues, it is crucial to implement strong authentication and authorization checks, validate input parameters, and follow best security practices when developing your applications. Implementing proper access controls, input validation, and security measures is essential to mitigate these risks and protect your applications and systems from these potential consequences.

Conclusion

In this topic, we learn about POLP a.k.a the Least Privilege Principle. Its main purpose is to enhance security by limiting unnecessary access and permissions, reduce potential attack vectors, and minimize the impact of security breaches which is one of the fundamental aspects of modern cybersecurity.