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

The term ‘availability’ in the context of Secure Software Development Lifecycle (SDL) refers to ensuring that systems, applications, and data are accessible to authorized users when needed. This means that the information must be timely and reliable, without undue delays or interruptions. Availability is a critical aspect of security, as it ensures that the software functions correctly and efficiently, providing users with the information they need to perform their tasks.

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.

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.

Manual peer review refers to the systematic examination of software source code by developers other than the original author. This practice is recognized as a valuable tool for reducing software defects and improving the quality of software projects. It involves developers inspecting the code to find and fix mistakes overlooked in the initial development phase, which enhances both the overall quality of software and the developers’ skills. Peer code review is less formal and more “lightweight” than the code inspections performed in the past, and it provides benefits such as knowledge transfer, increased team awareness, and creation of alternative solutions to problems.

The task described involves assessing a document management application that has been in use for many years. This scenario typically requires a security strategy that addresses the unique challenges of legacy code. Legacy code refers to software that has been around for a long time and may not have been developed with current security standards in mind. A security strategy for legacy code would include measures to ensure that the application complies with current organizational policies, which may involve code reviews, updates, and the implementation of modern security practices to mitigate any potential vulnerabilities inherent in older code12.

To remediate the vulnerability of servers responding to ping requests with sensitive information, the organization should configure the servers to return as little information as possible to network requests. This practice is known as reducing the attack surface. By limiting the amount of information disclosed, potential attackers have less data to use when attempting to exploit vulnerabilities. Regular updates and patching (Option B) are also important, but they do not address the specific issue of information disclosure. Uninstalling or disabling unnecessary features (Option C) and restricting access to configuration files (Option D) are good security practices, but they do not directly prevent the leakage of server information through ping responses.

In the PASTA (Process for Attack Simulation and Threat Analysis) threat modeling methodology, vulnerability and exploit analysis is performed during the Attack modeling step. This step involves identifying potential threats and vulnerabilities within the system and understanding how they could be exploited.

Attack modeling is a critical phase where the focus is on simulating attacks based on identified vulnerabilities. It allows for a deep understanding of the threats in the context of the application’s architecture and system design.

During this phase, security analysts use their knowledge of the system’s technical scope and application decomposition to simulate how an attacker could exploit the system’s vulnerabilities. This helps in prioritizing the risks and planning appropriate mitigation strategies.

The goal of attack modeling is not just to identify vulnerabilities but also to understand the potential impact of exploits on the system and the business, which is essential for developing a robust security posture.

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.

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.

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.

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 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.

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.

Comprehensive and Detailed In-Depth Explanation:

The scenario describes a stage where the developed features are deployed to a pre-production environment for verification by analysts. This aligns with the Testing phase of the Software Development Life Cycle (SDLC).

In the Testing phase, the system undergoes various evaluations to ensure it meets the specified requirements and functions correctly. This includes deploying the software in an environment that simulates production to identify and rectify defects before the actual deployment. The primary goal is to validate the software's quality and performance.

According to the SDLC framework, after the development (coding) phase, the next step is Testing, where the system is rigorously evaluated. This phase is crucial to detect issues that may not have been apparent during development and to ensure that the software operates as intended in a controlled setting before live deployment.

The phase being described is the Deployment phase of the SDLC. This phase involves making the software available for use by customers after it has been developed, tested, and approved for release. It includes the installation of the software in the production environment, ensuring that all features are operational as intended, and obtaining formal approval from leadership to proceed with making the product available to end-users. The deployment phase is critical as it transitions the software from a development setting to a real-world operational environment.

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 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.

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.

Fuzz testing is the ideal technique in this scenario. Here's why:

Focus on Integrations: The scenario emphasizes testing links between the software, databases, web servers, and web services. Fuzz testing is specifically designed to find vulnerabilities in how software handles data and communication between components.

Pre-release Testing: The product being close to release indicates a critical need to identify security flaws before public deployment. Fuzz testing is effective in uncovering unexpected behavior and potential vulnerabilities.

Fuzz Testing Targets: Fuzz testing works by injecting invalid or unexpected data into interfaces (like those between databases, web components, etc.) to observe how the software reacts. This helps expose potential security gaps and weaknesses.

The security testing technique that involves using a testing tool to scan a running application for known exploit signatures is known as Automated Vulnerability Scanning. This method is part of dynamic analysis, which assesses the software in its running state to identify vulnerabilities that could be exploited by attackers. Automated vulnerability scanning tools are designed to detect and report known vulnerabilities by comparing the behavior and outputs of the application against a database of known exploit signatures1.