Secure-Software-Design Questions and Answers

The secure coding practice being described is Access Control. This practice ensures that access to data and features within a system is restricted and controlled. The description given indicates that the product has mechanisms to prevent the display of personally identifiable information (PII), restrict the printing of private documents, and require elevated privileges to access archived documents. These are all measures to control who has access to what data and under what circumstances, which is the essence of access control.

The issue described involves a session management vulnerability where the user’s session remains active even after the browser window is closed, allowing another user on the same machine to access the application without logging in. To prevent this security risk, it’s essential to adjust the session management controls to include an automatic timeout feature. This means that after a period of inactivity, or when the browser window is closed, the session should automatically expire, requiring a new login to access the application. This adjustment ensures that even if a user forgets to log out, their session won’t remain active indefinitely, reducing the risk of unauthorized access.

Fuzzing is an automated or semi-automated software testing technique that involves providing invalid, unexpected, or random data to the inputs of a computer program1. This process is designed to uncover coding errors, security vulnerabilities, and other potential issues within the software by observing how it behaves under unexpected or malformed inputs. Fuzzing is particularly effective because it can expose corner cases that have not been properly dealt with and can be used to test programs that take structured inputs, such as file formats or protocols2.

The secure coding best practice that emphasizes treating all incoming data as untrusted and subjecting it to validation is known as input validation. This practice is crucial for ensuring that a system only processes valid, clean data, thereby preventing many types of vulnerabilities, such as SQL injection, cross-site scripting (XSS), and buffer overflows, which can arise from maliciously crafted inputs.

Input validation involves verifying that the data meets certain criteria before it is processed by the system. This includes checking for the correct data type, length, format, and range. It also involves sanitizing the data to ensure that it does not contain any potentially harmful elements that could lead to security breaches.

A centralized input validation routine is recommended for the entire application, which helps in maintaining consistency and effectiveness in the validation process. This routine should be implemented on a trusted system, typically server-side, to prevent tampering or bypassing of the validation logic.

It’s important to classify all data sources into trusted and untrusted categories and to apply rigorous validation to all data from untrusted sources, such as user input, databases, file streams, and network interfaces.

By adhering to the input validation best practice, developers can significantly reduce the attack surface of their applications and protect against a wide array of common security threats.

The deliverable that would aid a software security team in preparing a detailed schedule mapping security development lifecycle phases to the type of analysis they will execute is Security test plans. These plans are crucial as they outline the testing strategies and specific security tests that will be conducted during the development lifecycle to ensure the software meets the required security standards.

Security test plans are developed after the requirements and design phases and are used throughout the implementation, verification, and release phases. They include detailed instructions for security testing, criteria for success, and the types of security testing to be performed, such as static and dynamic analysis, penetration testing, and code review.

These plans are living documents that should be updated as new threats are identified and as the project evolves. They ensure that all team members understand the security goals, the risks, and the measures that need to be taken to mitigate those risks.

By having a well-defined security test plan, the team can ensure that security is not an afterthought but is integrated into every phase of the software development lifecycle, thus producing more secure software.

The software control test that examines an application from a user perspective by providing a wide variety of input scenarios and inspecting the output is known as black box testing. This testing method focuses on the functionality of the application rather than its internal structures or workings. Testers provide inputs and examine outputs without knowing how and where the inputs are worked upon. It’s designed to test the system’s external behavior.

Black box testing is used to verify that the system meets the requirements and behaves as expected in various scenarios, including edge cases and incorrect input data. It helps in identifying discrepancies between the system’s actual functionality and its specified requirements.

This type of testing is applicable across various levels of software testing, including unit, integration, system, and acceptance testing. It is particularly useful for validating user stories and use cases during the software development process.

Since black box testing treats the software as a “black box”, it does not require the tester to have knowledge of the programming languages or the system’s implementation. This allows testers to objectively test the software’s behavior and performance.

Comprehensive and Detailed Explanation From Exact Extract:

A Threat profile is a security assessment deliverable that outlines and identifies possible security vulnerabilities and threats relevant to a product. It includes categorization of threats, their potential impact, and vectors through which the product can be attacked. This deliverable is crucial for guiding mitigation and security testing efforts. Metrics templates (B) track progress or measurements, SDL project outline (C) documents phases and tasks in the secure development lifecycle, and the list of third-party software (D) catalogs external dependencies but does not specifically identify vulnerabilities. As per Microsoft SDL and OWASP Threat Modeling, the threat profile is a foundational deliverable in risk assessment and vulnerability identification.

White box testing, also known as clear box testing, glass box testing, transparent box testing, and structural testing, is a method of software testing where the internal structure, design, and coding of the software are tested to verify the flow of input-output and to improve the design, usability, and security. It involves looking at the structures that are internal to the system, with the tester having knowledge of the internal workings of the product. This type of testing is concerned with examining the internal logical structures of the program and is typically performed by stepping through the code line by line to analyze the program for potential errors, which aligns with the description of the control test in question.

Option D best addresses security change management, here's why:

Focus on Change: The question directly asks about a modification to how remote administration is secured. This aligns with the core goal of security change management, which is to evaluate and control the security implications of changes to systems.

Security-Specific: The question is explicitly concerned with security, not general functionality or requirements.

Practical Aspect: Remote administration access is a frequent target for attackers, making it a common area for security change management scrutiny.

ASF Authentication Threats: The Web Application Security Frame (ASF) authentication category encompasses threats related to how users and systems prove their identity to the application. This includes issues like weak passwords, compromised credentials, and inadequate access controls.

Role-Based Access Control (RBAC): RBAC is a well-established security principle that aligns closely with addressing authentication threats. It involves assigning users to roles and granting those roles specific permissions based on the principle of least privilege. This limits the attack surface and reduces the impact of a compromised user account.

Let's analyze the other options:

B. Credentials and tokens are encrypted: While vital for security, encryption primarily protects data at rest or in transit. It doesn't directly address authentication risks like brute-force attacks or weak password management.

C. Cookies have expiration timestamps: Expiring cookies are a good practice, but their primary benefit is session management rather than directly mitigating authentication-specific threats.

D. Sensitive information is scrubbed from error messages: While essential for preventing information leakage, this practice doesn't address the core threats within the ASF authentication category.

The issue described involves a PATCH request causing an unhandled server exception because the API does not support this method. The most direct and effective way to prevent such exceptions is to ensure that the API is configured to accept only the supported request methods: GET, POST, PUT, and DELETE. This can be achieved by implementing strict input validation to reject any requests that do not conform to the defined API specifications, including the request method. By doing so, any requests using unsupported methods like PATCH will be immediately rejected, thus preventing the server from reaching an exception state.

 Session management is a core component of secure coding, which involves maintaining the state of a user’s interaction with a system. Proper session management can help protect against various security vulnerabilities, such as session hijacking and session fixation attacks. It is essential for ensuring that user data is handled securely throughout an application’s workflow.

Comprehensive and Detailed Explanation From Exact Extract:

Throttling is a common and effective mitigation technique against Denial of Service (DoS) attacks. It limits the number of requests a user or IP can send over a certain time period, preventing resource exhaustion. This reduces the risk of overwhelming servers, which is the core issue in DoS attacks. Digital signatures (A) protect data integrity and authenticity, Protect secrets (B) secures confidential information, and Timestamps (C) help prevent replay attacks but are not direct defenses for DoS. According to NIST SP 800-61 Rev. 2 (Computer Security Incident Handling Guide) and OWASP DoS Prevention, throttling and rate limiting are standard controls to maintain availability under attack conditions.

Comprehensive and Detailed Explanation From Exact Extract:

The Iterative software development model fits this description. It involves specifying and implementing a portion of the software, reviewing it, gathering feedback, and refining or adding requirements in successive cycles. This approach supports evolving requirements and continuous improvement. Iterative models contrast with Waterfall (C), which is linear and sequential, with no repetition of phases. “Code and fix” (D) is an informal, ad hoc process lacking formal review cycles. Implementation (B) is a phase, not a model. The iterative approach is advocated in ISO/IEC 12207 and NIST guidelines for secure development, as it allows early detection and remediation of security issues by incremental design and testing.

 The principle of running with the least privilege is a fundamental security concept that involves granting users only the permissions they need to perform their tasks and no more. This minimizes the risk of a user gaining access to administrator-level functionality that they are not authorized to use. By limiting the privileges of user accounts to the bare minimum necessary, the potential damage from various attacks, such as privilege escalation, is significantly reduced.

The privacy impact statement requirement that defines how personal information will be protected when authorized or independent external entities are involved is best categorized under Third party requirements. This aspect of privacy impact assessments ensures that personal data is safeguarded even when it is necessary to involve third parties, which could be service providers, partners, or other entities that might handle personal information on behalf of the primary organization. These requirements typically include stipulations for data handling agreements, security measures, and compliance checks to ensure that third parties maintain the confidentiality and integrity of the personal information they process.

Authentication is the most effective control for the scenario because it directly addresses who is using the public computers:

User Identification: Authentication requires users to identify themselves (e.g., library card, login credentials) before accessing the computers. This links actions to specific individuals, making it easier to control unauthorized activity.

Policy Enforcement: Combined with other controls (e.g., content filtering), authentication enables the library to implement policies restricting downloads. If users violate the policy, their identities can be used for consequences.

Deterrent: Knowing they can be identified discourages users from attempting illegal downloads.

The activity being performed is the final privacy review. This step is crucial in the Ship phase of the Security Development Lifecycle (SDL), where the security team assesses if there are any changes or unresolved issues that could impact the requirements for handling personal information. These requirements are typically documented in the earlier stages of the development lifecycle, and the final privacy review ensures that the software complies with these requirements before release.

The phase being described is the Implementation phase of the SDLC. During this phase, the actual development starts, and the product begins to be built. The teams are actively writing code, which is a key activity of the Implementation phase. This phase involves translating the design and specifications into executable code, developing the software’s features, and then integrating the various components into a full-fledged system.

Security change management within the change management process involves ensuring that any changes, including updates or modifications to software, do not introduce new vulnerabilities and are in line with security policies. The question about securing remote administration directly reflects this component because it addresses the security considerations that must be managed when changes are made to how software is accessed and controlled remotely. This includes implementing secure protocols, authentication methods, and monitoring to prevent unauthorized access or breaches, which are crucial when managing changes in a secure manner.