The best answer is C. Isolation.

The question describes an application that can no longer be patched, meaning the organization must continue operating it while accepting some risk. To reduce exposure, the application should only be used by a limited number of network services. This points to isolation, which means restricting the application’s interaction with the rest of the environment to contain risk.

Isolation is commonly used for:

legacy systems

unsupported applications

unpatchable systems

high-risk services that must remain operational

By isolating the application, the organization limits the paths through which it can be attacked and reduces the chance that a compromise will spread to other systems.

Why the other options are incorrect:

A. PatchingThe question clearly states that no additional patches can be applied.

B. SegmentationSegmentation is related and often used as a method to isolate systems, but the question asks for the best description of the mitigation approach overall. Since the application is being restricted because it is risky and unpatchable, isolation is the stronger answer.

D. MonitoringMonitoring helps detect issues but does not directly reduce exposure in the way described.

From the SY0-701 perspective, when a vulnerable or unsupported application must remain in use, the preferred mitigation is often to isolate it from the broader environment. Therefore, C is the best answer.

Monolithic code architecture significantly limits an organization’s ability to benefit from containerization. Containers are designed to package and run small, modular, loosely coupled services, often following a microservices architecture. CompTIA Security+ SY0-701 explains that containers enhance security by reducing attack surface, improving isolation, and allowing granular patching—but only when applications are designed to support this model.

Monolithic applications bundle all components (UI, business logic, database access) into a single large codebase. This makes it difficult to isolate functions into separate containers, apply least privilege, or patch individual components without redeploying the entire application. As a result, security improvements such as rapid updates, minimal images, and fine-grained access controls are harder to achieve.

Regulatory compliance (A) may add requirements but does not inherently block container use. Patch availability (B) affects maintenance but not architecture suitability. Kernel version (C) can be a constraint, but modern container platforms manage kernel compatibility effectively.

Because containers are best suited for modular applications, monolithic code is the primary limitation, making D the correct answer.

Placing a false (decoy) text file in a sensitive location (such as /docs/salaries) is an example of a honeytoken or deception technique. This technique is used to attract insider attackers and monitor their actions when they attempt to access the file.

An endpoint detection and response (EDR) system is a security tool that monitors and analyzes the activities and behaviors of endpoints, such as computers, laptops, mobile devices, and servers. An EDR system can detect, prevent, and respond to various types of threats, such as malware, ransomware, phishing, and advanced persistent threats (APTs). One of the features of an EDR system is to block the automatic execution of downloaded programs, which can prevent malicious code from running on the endpoint when a user clicks on a link in a phishing message. This can reduce the impact of a phishing attack and protect the endpoint from compromise. Updating the EDR policies to block automatic execution of downloaded programs is a technical control that can mitigate the risk of phishing, regardless of the user’s awareness or behavior. Therefore, this is the best answer among the given options.

The other options are not as effective as updating the EDR policies, because they rely on administrative or physical controls that may not be sufficient to prevent or stop a phishing attack. Placing posters around the office to raise awareness of common phishing activities is a physical control that can increase the user’s knowledge of phishing, but it may not change their behavior or prevent them from clicking on a link in a phishing message. Implementing email security filters to prevent phishing emails from being delivered is an administrative control that can reduce the exposure to phishing, but it may not be able to block all phishing emails, especially if they are crafted to bypass the filters. Creating additional training for users to recognize the signs of phishing attempts is an administrative control that can improve the user’s skills of phishing detection, but it may not guarantee that they will always be vigilant or cautious when receiving an email. Therefore, these options are not the best answer for this question. References = Endpoint Detection and Response – CompTIA Security+ SY0-701 – 2.2, video at 5:30; CompTIA Security+ SY0-701 Certification Study Guide, page 163.

According to the shared responsibility model, the client and the cloud provider have different roles and responsibilities for securing the cloud environment, depending on the service model. In an IaaS (Infrastructure as a Service) model, the cloud provider is responsible for securing the physical infrastructure, such as the servers, storage, and network devices, while the client is responsible for securing the operating systems, applications, and data that run on the cloud infrastructure. Therefore, the client is responsible for securing the company’s database in an IaaS model for a cloud environment, as the database is an application that stores data. The client can use various security controls, such as encryption, access control, backup, and auditing, to protect the database from unauthorized access, modification, or loss. The third-party vendor and the DBA (Database Administrator) are not roles defined by the shared responsibility model, but they may be involved in the implementation or management of the database security. References = CompTIA Security+ SY0-701 Certification Study Guide, page 263-264; Professor Messer’s CompTIA SY0-701 Security+ Training Course, video 3.1 - Cloud and Virtualization, 5:00 - 7:40.

A group policy object (GPO) is a mechanism for applying configuration settings to computers and users in an Active Directory domain. By pushing a GPO update, the systems administrator can quickly and uniformly enforce the new password policy across all systems in the domain. Deploying PowerShell scripts, enabling PAP, and updating EDR profiles are not the most efficient or effective ways to change the password policy within an enterprise environment. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, page 115; Password Policy - Windows Security

Infrastructure as code (IaC) is a method of using code and automation to manage and provision cloud resources, such as servers, networks, storage, and applications. IaC allows for easy deployment, scalability, consistency, and repeatability of cloud environments. IaC is also a key component of DevSecOps, which integrates security into the development and operations processes. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, Chapter 6: Cloud and Virtualization Concepts, page 294.

Password spraying is a type of attack where an attacker tries a small number of commonly used passwords across a large number of accounts. The event logs showing failed login attempts for many user accounts from the same IP address are indicative of a password spraying attack, where the attacker is attempting to gain access by guessing common passwords.

References = CompTIA Security+ SY0-701 study materials, particularly in the domain of identity and access management and common attack vectors like password spraying​​.

Homomorphic encryption allows data to be encrypted and manipulated without needing to decrypt it first. This cryptographic technique would allow the financial institution to store customer data securely in the cloud while still permitting operations like searching andcalculations to be performed on the encrypted data. This ensures that the cloud service provider cannot decipher the sensitive data, meeting the institution’s security requirements.

References =

CompTIA Security+ SY0-701 Course Content: Domain 03 Security Architecture​.

CompTIA Security+ SY0-601 Study Guide: Chapter on Cryptographic Techniques​.

Comprehensive and Detailed Explanation From Exact Extract:

Infrastructure as Code (IaC) is the technology required for automating infrastructure deployment. IaC allows organizations to define and deploy servers, networks, containers, and cloud resources using machine-readable configuration files rather than manual configuration. This leads to faster deployment, consistent environments, repeatability, version control, and lower human error.

CompTIA Security+ SY0-701 highlights IaC as a foundational component of DevOps and modern cloud operations. It supports automated provisioning through tools such as Terraform, Ansible, CloudFormation, and Puppet. IaC also enhances security by enabling automated compliance checks and standardized hardened configurations.

IaaS (B) is a cloud service model, not an automation mechanism. IoC (C) refers to Indicators of Compromise used in threat intelligence. IoT (D) refers to Internet-connected devices and is unrelated to infrastructure deployment.

Therefore, IaC is the required technology for automated, repeatable, secure infrastructure deployments.

A vulnerability scan is the most effective method for identifying legacy systems within an environment. Vulnerability scanners assess hosts for outdated operating systems, unsupported software versions, missing patches, deprecated services, and known Common Vulnerabilities and Exposures (CVEs). CompTIA Security+ SY0-701 highlights vulnerability scanning as a foundational security operation used to gain visibility into system age, patch status, and configuration weaknesses.

Legacy systems often stand out in scan results because they run end-of-life operating systems, use deprecated protocols, or lack current security updates. These indicators allow security teams to quickly flag systems that require isolation, compensating controls, or replacement.

Bug bounty programs (A) rely on external researchers and are not designed to inventory internal assets. Package monitoring (C) tracks software behavior and changes but does not identify system age or support status. Dynamic analysis (D) evaluates running applications for vulnerabilities, not infrastructure lifecycle status.

Because vulnerability scans provide broad visibility into system versions and supportability, the correct answer is B: Vulnerability scan.

Segmentation is a network design technique that divides the network into smaller and isolated segments based on logical or physical boundaries. Segmentation can help improve network security by limiting the scope of an attack, reducing the attack surface, and enforcing access control policies. Segmentation can also enhance network performance, scalability, and manageability. To accomplish the goal of storing customer data on a separate part of the network, the administrator can use segmentation technologies such as subnetting, VLANs, firewalls, routers, or switches. References: CompTIA Security+ Study Guide: Exam SY0-701, 9th Edition, page 308-309 1