Comparison of STRIDE, DREAD & PASTA

TL;DR:

• The blog post compares STRIDE, DREAD, and PASTA threat modelling frameworks.
• STRIDE is simple and suitable for small organizations, DREAD is quantitative and for mature security practices, while PASTA is comprehensive and ideal for large organizations.
• Factors to consider when choosing a framework include complexity, use case, output, and ease of use.
• Each framework has its strengths and weaknesses, and the choice depends on the organization's specific needs and circumstances.
• A combination of these frameworks may be used for more effective and comprehensive threat modelling.

The ever-evolving threat landscape demands constant vigilance. As security professionals, we must understand the potential risks and vulnerabilities lurking within our systems to protect our assets effectively. The increasing number of data breaches and cyberattacks in today's digital age highlights the importance of a proactive security approach. Threat modelling is one such approach.

Threat modelling helps identify potential threats to a system and provides a structured approach to mitigate them. But with multiple options, how will you know which is the best threat modelling framework for you? Don’t worry, we’re here to help you with that. Whether you're an experienced cybersecurity professional or a business owner looking to improve your organization's security posture, this blog will provide you with a deeper understanding of the strengths and limitations of each framework, helping you make an informed decision about which one to choose. In this blog post, we will delve into a detailed comparison of STRIDE, DREAD, and PASTA to help you choose the most suitable framework for your security needs.

Understanding Threat Modelling and its Connection to Penetration Testing

Threat modelling is a structured approach to identifying and evaluating potential security threats to a system. It involves analyzing the system's architecture, data flows, and user roles to identify potential attack vectors and threat actors. The goal is to identify and prioritize security risks so that appropriate countermeasures can be implemented to minimize/mitigate them.

Threat modelling and penetration testing are two essential approaches to identifying and addressing security vulnerabilities in software systems. While they share similar goals, they differ in their approach, methods, and scope. Threat modelling seeks to identify potential threats before they can be exploited, while penetration testing assesses the security of a system by attempting to exploit vulnerabilities. Threat modelling is about assessing the overall security posture of a system from a theoretical perspective and mitigating weaknesses, while penetration testing is about manually assessing the security of a system in a more practical sense by simulating attacks.

Ideally, threat modelling should be performed early in the penetration testing process, during the scoping and planning phase. This allows organizations to identify potential attack vectors and prioritize them for testing during the penetration test. By doing so, organizations can ensure that the penetration test is focused on the most critical vulnerabilities and that their resources are being used effectively.

Now that we understand the importance of threat modelling and how it relates to penetration testing, let's dive into some of the popular threat modelling frameworks available for threat modelling: STRIDE, DREAD, and PASTA. Let's take a closer look at these frameworks and how they can help improve security.

Exploring the STRIDE, DREAD, and PASTA Frameworks for Threat Modeling

Considering the STRIDE Framework

STRIDE stands for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, and Elevation of Privilege. Each of these categories represents a potential attack vector that can be exploited by threat actors.

• Spoofing: Refers to an attacker impersonating a legitimate user or system to gain access or deceive others.
• Tampering: Involves unauthorized modification of data or systems, such as changing values or altering code.
• Repudiation: Deals with denying an event or action that has taken place, which can be used to hide malicious activity.
• Information Disclosure: This involves exposing sensitive information to unauthorized parties, which can be used to exploit or harm individuals or organizations.
• Denial of Service: Refers to the disruption or prevention of authorized access to systems or resources, often by overwhelming them with requests.
• Elevation of Privilege: This occurs when an attacker gains higher levels of access or privileges than intended, allowing them to perform unauthorized actions or access sensitive data.

The STRIDE framework works by systematically analyzing each of these categories to identify potential threats and vulnerabilities. The framework then categorizes the identified threats into specific threat classes. For example, spoofing attacks involve impersonating another user or system, while tampering involves modifying data in transit or at rest. This is particularly useful when organizations plan to mitigate entire classes of threats by using class-specific controls rather than threat-specific controls. For example, deploying a Web Application Firewall (WAF) can mitigate an entire class of web application vulnerabilities. By analyzing each of these categories, organizations can identify potential threats and prioritize them for mitigation.

Mostly used for application security, STRIDE can also be extended to network security. The STRIDE framework provides a structured and systematic approach to threat modelling. It helps organizations identify potential threats and vulnerabilities in a consistent and repeatable way, which can improve the effectiveness of their security efforts.

However, the STRIDE framework can be time-consuming and resource-intensive. It requires a significant amount of effort to analyze each of the categories and identify potential threats, which can be a challenge for organizations with limited resources.

Assessing the DREAD Framework

DREAD stands for Damage, Reproducibility, Exploitability, Affected Users, and Discoverability.

• Damage: Refers to the potential impact that a vulnerability could have on the target. The target can be the organization, the system in question, or other users in general.
• Reproducibility: Refers to how easily the vulnerability can be reproduced by an attacker.
• Exploitability: Refers to how easy or difficult it is to exploit the vulnerability.
• Affected Users: Refers to the number of users who could be affected by the vulnerability.
• Discoverability: Refers to how easy or difficult it is to discover the vulnerability.

This framework works by assigning a score of 0-10 to each of the categories to rate the severity of the potential threat. The scores are then added together to provide an overall score, which is used to prioritize which threats to focus on. You can compare DREAD to the Common Vulnerability Scoring System (CVSS) in terms of how it measures the severity of identified threats. Software Secured uses both DREAD and CVSS combined when scoring vulnerabilities.

The DREAD framework can be used to assess the severity of individual threats that have already been identified through the use of other methodologies, such as STRIDE. Once a threat has been identified, DREAD helps to measure its potential severity by assigning scores. Its methodology can provide a quick and effective way to identify and prioritize potential threats and allows organizations to focus on the most critical threats first.

However, the DREAD framework also has some limitations. One such limitation is that it is focused solely on technical threats and does not consider other factors that could impact the severity of a potential threat, such as the impact on business operations or reputation. Additionally, the framework may not provide sufficient detail to fully assess the severity of a potential threat, and the scores assigned to each category may be subjective and vary based on individual perspectives.

Evaluating the PASTA Framework

PASTA stands for Process for Attack Simulation and Threat Analysis. It is a seven-step methodology used to identify, analyze and prioritize threats and attacks in software applications. The PASTA framework is comprehensive and focuses on a risk-based approach to threat modelling.

The PASTA methodology follows a seven-step approach for threat modelling:

• Define Objectives: Identify the security objectives and goals of the system being modelled.
• Define Technical Scope: Define the technical scope of the system and its boundaries.
• Decomposition and Analysis: Decompose the system into smaller components and analyze each of them for potential threats.
• Threat Analysis: Identify and prioritize the potential threats and their attack vectors.
• Vulnerabilities and Weaknesses Analysis: Identify and analyze potential vulnerabilities and weaknesses in the system.
• Modeling and Simulation: Create a visual model using diagrams and simulations to assess the system's security posture.
• Risk Impact Analysis: Evaluate the risks associated with identified threats and vulnerabilities and prioritize them for risk mitigation.

PASTA is often used in organizations that have a mature security program in place. It can be used to guide the development of countermeasures to address the identified risks. This framework is flexible, allowing organizations to customize the methodology to meet their specific needs.

PASTA requires a high level of expertise to implement correctly, and it is typically very time-consuming. It is also a complex methodology, which may not be suitable for smaller organizations with limited resources. Additionally, PASTA does not provide specific guidance on how to address the identified risks, which means that additional expertise may be required to develop an effective risk mitigation plan.

Now that we have explored the STRIDE, DREAD, and PASTA threat modelling frameworks, you may be wondering which is the best fit for your organization. Let’s discuss some key factors to consider when choosing a threat modelling framework and help you make an informed decision.

Determining the Best Threat Modeling Framework for Your Needs

Each of the threat modelling frameworks discussed above has its unique features and is best suited for certain types of organizations. The decision of which one to use ultimately depends on your specific needs and goals, such as business goals, the complexity of your system, and available resources. Let’s look into which threat modelling framework is right for you based on the type of organization.

Considering the STRIDE Framework

STRIDE is a popular threat modelling framework used by organizations of all sizes. It is best suited for organizations that are starting with threat modelling for the first time. STRIDE is a simple framework that can be easily implemented, making it ideal for small businesses and startups. It is also a good fit for organizations that are primarily concerned with software security, as it is designed specifically for this purpose. In addition, STRIDE can be used by organizations that have a limited budget for security, as it does not require expensive tools or software.

Assessing the DREAD Framework

DREAD proves to be particularly beneficial for organizations that are looking for a structured and quantitative approach to assess vulnerabilities and prioritize their remediation efforts. It fits well within organizations with complex systems and numerous interconnected components but may be challenging for organizations with limited resources as they might find this framework complex or time-consuming. Additionally, as mitigation suggestions are not part of the model, it is best interpreted by experienced security professionals.

DREAD enables you to efficiently prioritize efforts and focus on the vulnerabilities that pose the greatest risk to your organization's assets. Let’s say you are performing an e-commerce platform penetration test. DREAD can be used to prioritize testing efforts by assigning high scores for damage, exploitability, and affected users to vulnerabilities, such as those that allow an attacker to access customer data.

Evaluating the PASTA Framework

PASTA is a comprehensive threat modelling framework that is best suited for large and complex organizations. It is ideal for organizations that have a lot of different assets to protect, such as financial institutions, government agencies, and large corporations. PASTA is a highly customizable framework that allows organizations to tailor their threat modelling process to their specific needs. It is also a good fit for organizations that have a dedicated security team with the necessary expertise to implement a complex threat modelling framework. PASTA is not recommended for small or medium-sized organizations, as it requires a significant investment in time and resources to implement.

PASTA is recommended for established activities, particularly for use in synergy with risk management. For example, when assessing security for an enterprise-level organization, PASTA can identify critical assets such as customer data, financial information, and intellectual property, assess the impact of a breach, and develop a risk management strategy for protecting them.

Final Thoughts and Recommendations

When it comes to selecting a threat modelling framework for your organization, it is important to consider various factors such as the size of the organization, complexity, the goals of the threat modelling exercise, and the expertise of the team.

Each of the three frameworks, STRIDE, DREAD, and PASTA, has its strengths and weaknesses. STRIDE is a simple and easy-to-use framework suitable for smaller organizations or those with limited security expertise. DREAD is a great option for organizations with more mature security practices, looking for a comprehensive risk assessment framework. PASTA is ideal for larger organizations that require a more holistic approach and have a dedicated risk management team.

Ultimately, the choice of the framework depends on the specific needs and circumstances of your organization. It is also worth noting that a combination of these frameworks may be used for more effective and comprehensive threat modelling. In the comparison of STRIDE, DREAD, and PASTA, understanding the nuances of each framework is crucial for effective threat modelling.