Pass the CompTIA CySA+ CS0-003 Questions and answers with ExamsMirror

Reimaging the device is the most effective way to eliminate persistent malware because some sophisticated malware, such as rootkits and firmware-level threats, can survive traditional scans and removals.

If a system keeps getting reinfected after cleaning, it may indicate a deeply embedded persistent threat, possibly in:

The Master Boot Record (MBR) or EFI firmware.

A compromised system restore point.

A hidden backdoor left by the malware.

Why Not Other Options?

A (Update and scan in safe mode) → Might help, but if malware is persistent, it will likely return.

C (Upgrade OS) → Does not necessarily remove malware; some malware survives OS upgrades.

D (Secondary scanner) → Useful for detection but does not guarantee complete removal.

Best Practice:

Replace the hard drive to eliminate firmware-level infections.

Reimage the system from a known-good source.

Update the OS and security patches before reconnecting to the network.

The correct answer is C. False negative.

A false negative is a situation where an attack or a threat is not detected by a security control, even though it should have been. In this case, the SIEM rule was unable to detect an attack with nine failed logins, which is below the threshold of ten failed logins that triggers an alert. This means that the SIEM rule missed a potential attack and failed to alert the security analysts, resulting in a false negative.

A false positive is a situation where a benign or normal activity is detected as an attack or a threat by a security control, even though it is not. A true negative is a situation where a benign or normal activity is not detected as an attack or a threat by a security control, as expected. A true positive is a situation where an attack or a threat is detected by a security control, as expected. These are not the correct answers for this question.

Comprehensive Detailed Explanation:To effectively prevent Cross-Site Scripting (XSS) attacks, implementing appropriate security controls within the application code and at the network layer is critical. Here’s a breakdown of each option:

A. Implement an IPS in front of the web server

Explanation: Intrusion Prevention Systems (IPS) are primarily designed to detect and prevent network-based attacks, not application-layer vulnerabilities such as XSS. They do not specifically mitigate XSS threats effectively.

B. Enable MFA on the website

Explanation: Multi-factor authentication (MFA) strengthens user authentication but does not address XSS, which typically involves injecting malicious scripts rather than compromising user credentials.

C. Take the website offline until it is patched

While this might temporarily mitigate the risk, it is not a practical solution for ongoing operations, especially when effective preventative controls (e.g., WAF rules or code updates) can be implemented without disabling the service.

D. Implement a compensating control in the source code

Explanation: Implementing security controls at the code level is an effective way to mitigate XSS risks. This can involve proper input validation, output encoding, and utilizing libraries that sanitize user inputs. By addressing the root cause in the source code, developers prevent scripts from being injected or executed in the browser.

E. Configure TLS v1.3 on the website

Explanation: While TLS v1.3 secures the communication channel, it does not address XSS directly. XSS attacks manipulate client-side scripts, which TLS cannot prevent, as TLS only encrypts data in transit.

F. Fix the vulnerability using a virtual patch at the WAF

Explanation: Web Application Firewalls (WAFs) can mitigate XSS vulnerabilities by identifying and blocking malicious payloads. Virtual patching at the WAF level provides a temporary fix by preventing exploit attempts from reaching the application, giving developers time to implement a permanent fix in the source code.

A cloud access security broker (CASB) is a tool that can help reduce the risk of shadow IT in the enterprise by providing visibility and control over cloud applications and services. A CASB can enable policy enforcement by blocking unauthorized or risky cloud applications, enforcing data loss prevention rules, encrypting sensitive data, and detecting anomalous user behavior.

The NTP configuration on each system should be checked first, as it is essential for ensuring accurate and consistent time stamps across different systems. NTP is the Network Time Protocol, which is used to synchronize the clocks of computers over a network. NTP uses a hierarchical system of time sources, where each level is assigned a stratum number. The most accurate time sources, such as atomic clocks or GPS receivers, are at stratum 0, and the devices that synchronize with them are at stratum 1, and so on. NTP clients can query multiple NTP servers and use algorithms to select the best time source and adjust their clocks accordingly1. If the NTP configuration is not consistent or correct on each system, the time stamps of the logs and events may differ, making it difficult to correlate incidents across different systems. This can affect the security analysis and correlation of events, as well as the compliance and auditing of the network23. References: How the Windows Time Service Works, Time Synchronization - All You Need To Know, What is SIEM? | Microsoft Security

When documenting a physical incident in a network data closet, taking photos provides a clear and immediate record of the situation, which is essential for thorough incident documentation and subsequent investigation.

Proper documentation of an incident in a data closet should include taking photos of the impacted items. This provides visual evidence and helps in understanding the physical context of the incident, which is crucial for a thorough investigation. Backing up configuration files, recording connections, and creating network diagrams, while important, are not the primary means of documenting the physical aspects of an incident.

Comprehensive and Detailed Step-by-Step Explanation:Remediated incidents is a key performance indicator (KPI) that measures how effectively incidents are resolved and communicated during the incident response lifecycle. It reflects the program's success in mitigating risks and restoring normal operations. Other options (e.g., mean time to detect) are important metrics but do not directly measure reporting or communication effectiveness.

The threat was detected from the time the emails were sent at 8:30 a.m. to when the recipients started alerting the organization’s help desk about the email at 8:45 a.m., taking a total of 15 minutes. The detection time is the time elapsed between the occurrence of an incident and its discovery by the security team . The other options are either too short or too long based on the given information. References: : Detection Time : Incident Response Metrics: Mean Time to Detect and Mean Time to Respond

Risk scoringis the best method for prioritizing patching, as it considers factors likeCVSS severity, exploitability, asset criticality, and business impact​.

Option A (Affected hosts)is relevant but does notdetermine prioritywithout a risk assessment.

Option C (Mitigation strategy)is useful but focuses on alternative protections rather than prioritization.

Option D (Annual recurrence)is not a standard method for vulnerability prioritization.

Thus,B is the correct answer, asrisk scores allow organizations to prioritize patching efforts effectively​.