STRIDE Framework: Addressing Information Disclosure, Denial of Service, and Elevation of Privilege in Threat Modeling

The STRIDE Framework is a threat modeling methodology developed by Microsoft to help identify and categorize security threats in software and systems. STRIDE stands for Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service (DoS), and Elevation of Privilege—categories that cover the full spectrum of security risks faced by applications. Within the context of Governance, Risk, and Compliance (GRC) and threat modeling activities, the STRIDE framework enables organizations to systematically identify, assess, and mitigate threats, helping ensure compliance with security standards and proactive risk management.

This article focuses on three key STRIDE categories: Information Disclosure, Denial of Service, and Elevation of Privilege, discussing their relevance, risk factors, and mitigation strategies within threat modeling.

Overview of the STRIDE Framework

STRIDE provides a structured approach for identifying specific threats in a system, which are categorized as follows:

1. Spoofing: Impersonation of users, systems, or processes.
2. Tampering: Unauthorized modification of data or code.
3. Repudiation: Actions taken by users that cannot be tracked or attributed.
4. Information Disclosure: Unauthorized access to sensitive information.
5. Denial of Service (DoS): Disruption of service availability.
6. Elevation of Privilege: Gaining unauthorized privileges within a system.

By categorizing threats this way, STRIDE enables security teams to methodically address security gaps and design systems resilient to each type of threat.

Information Disclosure: Understanding and Mitigating the Risk of Data Exposure

Information Disclosure refers to the unauthorized exposure of sensitive information, such as personal data, intellectual property, or system details that could aid an attacker. Information disclosure can result in regulatory non-compliance, financial losses, and reputational damage.

Common Causes of Information Disclosure

• Insufficient Access Controls: Failure to restrict data access by role or privilege.
• Unencrypted Data in Transit or Storage: Lack of encryption can expose sensitive information to interception.
• Inadequate Logging and Monitoring: Without monitoring, unauthorized access may go undetected.
• Misconfigured APIs and Interfaces: Unsecured APIs can inadvertently reveal sensitive data to unauthorized users.

Mitigation Strategies for Information Disclosure

1. Implement Access Control Policies: Apply role-based access control (RBAC) and least privilege principles to limit data access to authorized users only.
2. Use Strong Encryption: Encrypt sensitive data at rest and in transit to prevent unauthorized access or interception.
3. Regularly Review and Configure APIs: Secure APIs by requiring authentication, minimizing data exposure, and using rate limiting to control access.
4. Audit Logs and Monitor Activity: Implement security information and event management (SIEM) tools to log access and detect potential data exposure incidents.

Denial of Service (DoS): Preventing Disruptions to Service Availability

Denial of Service (DoS) attacks aim to disrupt the availability of a service, making it inaccessible to legitimate users. This disruption can have severe financial and operational impacts, especially for critical systems and services.

Common Causes of DoS Vulnerabilities

• Lack of Rate Limiting: Without limits, a service can be overwhelmed by a high volume of requests.
• Insufficient Network Bandwidth: Low bandwidth can make systems more susceptible to network-based DoS attacks.
• Unoptimized Code and Resource Handling: Poor coding practices can lead to resource exhaustion under high traffic conditions.
• Single Points of Failure: Critical systems without redundancy are more likely to experience outages during DoS attacks.

Mitigation Strategies for Denial of Service

1. Implement Rate Limiting and Traffic Filtering: Apply rate limiting on APIs and services to control traffic flow and filter out high-frequency requests from malicious sources.
2. Use Content Delivery Networks (CDNs): CDNs can absorb large traffic volumes and provide load balancing, reducing the risk of DoS affecting system availability.
3. Optimize Code and Resource Management: Ensure that applications are designed to handle high traffic loads efficiently, with proper memory management and resource allocation.
4. Introduce Redundancy and Failover Mechanisms: Design systems with redundancy and failover to prevent single points of failure from disrupting service availability.

Elevation of Privilege: Addressing Risks of Unauthorized Access and Control

Elevation of Privilege occurs when an attacker gains higher-level access than their assigned permissions, allowing them to execute unauthorized actions, potentially compromising the entire system.

Common Causes of Elevation of Privilege

• Misconfigured User Roles: Incorrect user role configurations can inadvertently grant excessive permissions.
• Vulnerable Software: Unpatched vulnerabilities or bugs in code can provide attackers with avenues for privilege escalation.
• Lack of Privilege Segmentation: Failure to segment privileges by role increases the risk of unauthorized access.
• Weak Authentication and Authorization: Inadequate authentication mechanisms can be easily bypassed, leading to unauthorized privilege escalation.

Mitigation Strategies for Elevation of Privilege

1. Enforce Role-Based Access Control (RBAC): Clearly define user roles and limit permissions based on job functions to prevent unauthorized privilege escalation.
2. Regularly Patch and Update Software: Apply security patches and updates promptly to close vulnerabilities that could lead to privilege escalation.
3. Implement Strong Authentication: Use multi-factor authentication (MFA) to enhance login security, preventing unauthorized users from accessing higher privileges.
4. Conduct Privilege Audits: Regularly review user permissions and access controls to ensure that privilege levels remain appropriate and segmented.

Best Practices for Integrating STRIDE in Threat Modeling

Applying the STRIDE framework helps security teams proactively identify and mitigate risks across each threat category. Here are best practices for using STRIDE in threat modeling:

1. Develop Comprehensive Threat Models: For each component of the system, create a threat model that addresses all six STRIDE categories, evaluating vulnerabilities at each stage.
2. Prioritize Based on Impact: Use STRIDE as a guide to prioritize vulnerabilities, focusing on threats with the highest potential impact on business operations and compliance.
3. Use STRIDE Alongside OWASP and NIST: Complement STRIDE with frameworks like OWASP and NIST to ensure a thorough security strategy across all aspects of Governance, Risk, and Compliance.
4. Continuously Update and Review Threat Models: As systems evolve, update threat models regularly to address new risks and integrate emerging best practices.

Conclusion

The STRIDE framework offers a structured approach to identifying and mitigating a wide range of security threats, including Information Disclosure, Denial of Service (DoS), and Elevation of Privilege. By using STRIDE in threat modeling, organizations can systematically evaluate risks, enhance compliance, and reduce their attack surface. Incorporating STRIDE into Governance, Risk, and Compliance strategies ensures a comprehensive, proactive approach to security, protecting systems from vulnerabilities and ensuring a resilient security posture.

Frequently Asked Questions Related to STRIDE for Threat Modeling