Secure-Software-Design WGU Secure Software Design (D487, KEO1) Exam Question and Answers

Comprehensive and Detailed Explanation From Exact Extract:

CVSS scores are classified into severity levels based on numeric ranges. A base score of 9.9 falls within the Critical range (9.0–10.0), but after adjustment for temporal and environmental metrics, the score is 8.0, which falls into the High severity category (7.0–8.9). Therefore, the final rating assigned is High severity. Medium severity corresponds to scores between 4.0 and 6.9, and low severity is below 4.0. This scoring methodology is defined by the FIRST Common Vulnerability Scoring System v3.1 Specification which guides how scores are adjusted to reflect real-world risk contexts.

The step of the PASTA threat modeling methodology where the team will capture infrastructure, application, and software dependencies is the Define technical scope step. This step involves detailing the technical elements of the project, which includes understanding and documenting the infrastructure, applications, and software dependencies that are critical to the system’s operation and security.

The Intelligence domain in the Building Security in Maturity Model (BSIMM) focuses on gathering and using information about software security. This includes understanding the types of attacks that are possible against the software being developed, which is why reviewing attack models falls under this domain. The BSIMM domain of Intelligence involves creating models of potential attacks on software (attack models), analyzing actual attacks that have occurred (attack intelligence), and sharing this information to improve security measures. By reviewing attack models, the software security group is essentially assessing the organization’s ability to anticipate and understand potential security threats, which is a key aspect of the Intelligence domain.

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.

The core issue here is cleartext transmission of sensitive data, and option C directly addresses this:

Addressing the Problem: The scenario reveals the vulnerability is the lack of encryption during data transmission (the GET response). Ensuring encryption in transit fixes this specific exploit.

Transport Layer Security: Encryption during transit is typically achieved through protocols like TLS (HTTPS), preventing the interception of sensitive information.

The Common Vulnerability Scoring System (CVSS) uses the following ranges to determine the severity rating of a vulnerability:

0.1 - 3.9: Low severity

4.0 - 6.9: Medium severity

7.0 - 8.9: High severity

9.0 - 10.0: Critical severity

Since the adjusted score for the vulnerability is 5.9, it falls within the High severity range.

The practice described is Code review, which is a part of secure software development best practices. Code reviews are conducted to ensure that the code adheres to accepted coding patterns and meets the team’s quality standards. This process involves the examination of source code by a person or a group other than the author to identify bugs, security vulnerabilities, and ensure compliance with coding standards.

The phase being described is the Planning phase of the SDLC. This initial stage involves gathering business requirements and evaluating the feasibility of the project. It’s when the company leadership would typically meet with IT and other stakeholders to share visions for the future, discuss potential revenue streams, and determine the project’s direction before moving forward with development. This phase is crucial for setting the groundwork for all subsequent phases of the SDLC.

Comprehensive and Detailed Explanation From Exact Extract:

This is an example of Input validation, which involves ensuring all user inputs conform to expected formats, lengths, and content before processing. Restricting field lengths and validating accepted data types prevents injection attacks, buffer overflows, and improper data handling. Access control (B) restricts user permissions, communication security (C) protects data in transit, and data protection (D) focuses on confidentiality and integrity of stored data. OWASP Secure Coding Practices and Microsoft SDL emphasize rigorous input validation as a first line of defense against many vulnerabilities.

The activity described pertains to the review of noncommercial software libraries to ensure compliance with the legal specifications set by the authors. This is part of the open-source licensing review, which is a critical activity in the Ship phase of the Security Development Lifecycle (SDL). This review ensures that all open-source components are used in accordance with their licenses, which is essential for legal and security compliance.

The OpenSAMM business function being assessed is Verification. This function involves activities related to reviewing and testing to ensure that the software meets the required security standards and practices. In the context of the question, the software security group’s focus on reviewing design artifacts to ensure compliance with organizational security standards falls under the Verification function. This includes tasks such as design review, implementation review, and security testing, which are all aimed at verifying that the security measures and controls are correctly integrated into the software design.

The type of threat described is Tampering. This threat occurs when an attacker intercepts and manipulates data being sent from the client to the server, such as form data being submitted to an API. The attacker may alter the data to change the intended operation, inject malicious content, or compromise the integrity of the system. Tampering attacks are a significant concern in secure software design because they can lead to unauthorized changes and potentially harmful actions within the application.

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.

Security testing reports are the deliverables that typically contain detailed results of the security evaluations performed. These reports include the types of tests conducted, such as static and dynamic analysis, penetration testing, and code reviews, as well as the number and types of vulnerabilities discovered. The purpose of these reports is to document the security posture of the software at the time of testing and to provide a basis for remediation efforts.

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.

The last step of the SDLC code review process is to review the code for security issues. This involves a detailed examination of the code to identify any potential security vulnerabilities that could be exploited. It’s a critical phase where the focus is on ensuring that the code adheres to security best practices and does not contain any flaws that could compromise the security of the application or system. The process typically includes manual inspection as well as automated tools to scan for common security issues. The goal is to ensure that the software is as secure as possible before it is deployed. References: Mastering the Code Review Process, Understanding the SDLC, How Code Reviews Improve Software Quality in SDLC - LinkedIn.

The secure coding best practice that recommends using a single application-level authorization component to lock down the application if it cannot access its configuration information is known as Access Control. This practice is part of a broader set of security measures aimed at ensuring that only authorized users have access to certain functionalities or data within an application. By centralizing the authorization logic, it becomes easier to manage and enforce security policies consistently across the application. If the authorization component cannot retrieve its configuration, it defaults to a secure state, thus preventing unauthorized access1.

The Asset-centric approach to threat modeling focuses on identifying and protecting the assets that are most valuable to an organization. This method prioritizes the assets themselves, assessing their sensitivity, value, and the impact on the business should they be compromised. It is a strategic approach that aims to safeguard the confidentiality, integrity, and availability of the organization’s key assets.

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.

 The category that classifies identified threats with no defenses in place, exposing the application to exploits, is Unmitigated Threats. This term refers to vulnerabilities for which no countermeasures or mitigations have been implemented. These threats are critical because they represent actual weaknesses that attackers can exploit. In the context of secure software design, it’s essential to identify these threats early in the SDLC to ensure that appropriate security controls can be designed and implemented to protect against them.

Comprehensive and Detailed In-Depth Explanation:

Transmitting data in a human-readable format, such as JSON, over an API can expose sensitive information if the communication channel is not secure. To protect the confidentiality and integrity of the data, it's essential to encrypt all requests and responses between clients and servers.

Implementing encryption, typically through protocols like HTTPS (which utilizes TLS/SSL), ensures that data transmitted over the network is not readable by unauthorized parties. This prevents potential attackers from intercepting and understanding the data, thereby safeguarding sensitive information contained within the API communications.

This practice is a fundamental aspect of secure software development and aligns with the Implementation business function of the OWASP SAMM. Within this function, the Secure Build practice emphasizes the importance of configuring the software to operate securely in its intended environment, which includes enforcing encryption for data in transit.