Threat modeling your authentication system

Threat Modeling Your Authentication System

As software engineers, we often focus on building features and ensuring performance. However, one of the most critical aspects of system security is threat modeling. By understanding the potential vulnerabilities in your authentication system, you can proactively mitigate risks and ensure the integrity of your users' identities.

What Is Threat Modeling?

Threat modeling is a structured process of identifying, analyzing, and mitigating potential threats to your system. It helps you understand the attack surface of your application and prioritize security improvements.

One of the most widely used frameworks for threat modeling is STRIDE. This acronym stands for:

• Spoofing – impersonating a user
• Tampering – altering data
• Repudiation – denying actions
• Information Disclosure – exposing sensitive data
• Denial of Service – overwhelming the system
• Elevation of Privilege – gaining unauthorized access

Applying STRIDE to Authentication Flows

Let's walk through a practical example of applying STRIDE to an authentication flow. Consider a simple login system that uses a username and password to authenticate users.

Here's how STRIDE applies to this system:

• Spoofing – An attacker could impersonate a user by guessing or stealing their credentials.
• Tampering – An attacker could modify the authentication data in transit, leading to unauthorized access.
• Repudiation – A user could deny having performed an action, such as logging in, if the system doesn't provide non-repudiable evidence.
• Information Disclosure – If the system logs or stores sensitive information, such as passwords, it could be exposed to attackers.
• Denial of Service – An attacker could overwhelm the authentication system with excessive login requests, leading to service disruption.
• Elevation of Privilege – If the system grants excessive privileges to authenticated users, an attacker could exploit this to gain unauthorized access.

By identifying these threats, you can implement specific mitigations, such as:

• Using multi-factor authentication to prevent spoofing
• Encrypting data in transit to prevent tampering
• Implementing non-repudiable logging to prevent repudiation
• Storing credentials securely to prevent information disclosure
• Rate-limiting login requests to prevent denial of service
• Implementing role-based access control to prevent elevation of privilege

Why Bastionary Matters in This Context

As a self-hosted authentication platform, Bastionary provides the tools and flexibility needed to implement robust threat modeling strategies. With features like multi-factor authentication, role-based access control, and secure credential storage, Bastionary enables teams to build and maintain secure authentication systems that are resilient to STRIDE threats.

Whether you're building a small internal application