CS0-003 CompTIA CyberSecurity Analyst CySA+ Certification Exam Free Practice Exam Questions (2026 Updated)

The correct answer is A. System hardening.

System hardening is the process of securing a system by reducing its attack surface, applying patches and updates, configuring security settings, and implementing security controls. System hardening can help prevent or mitigate vulnerability events that may affect operating systems. Host-based IPS, firewalls, and two-factor authentication are examples of security controls that can be applied to harden a system1.

The other options are not the best descriptions of the scenario. A hybrid network architecture (B) is a network design that combines on-premises and cloud-based resources, which may or may not involve system hardening. Continuous authorization © is a security approach that monitors and validates the security posture of a system on an ongoing basis, which is different from system hardening. Secure access service edge (D) is a network architecture that delivers cloud-based security services to remote users and devices, which is also different from system hardening.

C. Impossible geo-velocity: This is an event where a single user ' s account is accessed from different geographical locations within a timeframe that is impossible for normal human travel. In the log, we can see that the user " jdoe " is accessing from the United States and then within a few minutes from Russia, which is practically impossible to achieve without the use of some form of automated system or if the account credentials are being used by different individuals in different locations.

B. Push phishing: This could also be an indication of push phishing, where the user is tricked into approving a multi-factor authentication request that they did not initiate. This is less clear from the logs directly, but it could be inferred if the user is receiving MFA requests that they are not initiating and are being approved without their genuine desire to access the resources.

To improve the detection of known attacks and behavioralIndicators of Compromise (IoCs), the best approach is tointegrate with an open-source threat intelligence feed. Threat intelligence feeds provide up-to-date information on known malicious IPs, domains, file hashes, and behavioral patterns that attackers use​.

Option A (randomly generating and storing hash values)is impractical, as there are an infinite number of possible files.

Option B (alerting on any system change)would lead to excessive noise and false positives, making the system difficult to manage.

Option D (manually adding signatures)is useful but is not scalable or as timely as an external intelligence feed​.

Thus, the correct answer isC, as integrating an open-source threat intelligence feed enhances the SIEM’s ability to detect and respond to real-world threats​.

The MITRE ATT & CK framework is widely used for tracking and categorizing Tactics, Techniques, and Procedures (TTPs) of adversaries. TTPs help analysts understand the behaviors and methods attackers employ during incidents, making this framework particularly useful in SIEM dashboards for correlating and identifying threats. While the other options (OSSTMM, Diamond Model, OWASP) offer various security methodologies, MITRE ATT & CK is specifically focused on documenting adversary behaviors, making it the best fit here. CompTIA CySA+ often emphasizes MITRE ATT & CK for mapping and understanding threat behaviors in incident response.

To identify existing vulnerabilities in the web application, the best options are to contract a penetration test and create a bug bounty program. A penetration test simulates attacks against the application to uncover security flaws proactively. A bug bounty program incentivizes external security researchers to find and report vulnerabilities, expanding the testing scope without overburdening internal resources. According to CompTIA CySA+, both methods are highly effective in identifying vulnerabilities from an external perspective, particularly when internal resources are limited. Options like a WAF (A) focus more on prevention than detection, while threat modeling (F) and tabletop exercises (D) are generally proactive measures not focused on active flaw identification.

Enabling a user account lockout policy is a security measure that can effectively mitigate brute-force attacks. After a predetermined number of consecutive failed login attempts, the account will be locked, preventing the attacker from continuing to try different password combinations. This control directly addresses the issue of multiple failed attempts from the same IP address using a single user account, making it the most effective among the options provided. Option B suggests replacing RDP with another remote access tool, which does not address the brute-force attempt but rather avoids the RDP protocol. Option C, implementing a firewall block, could be effective but does not prevent attacks from other IP addresses and may not be as immediate. Option D, increasing log verbosity, enhances monitoring but does not prevent the attack itself.

The scenario indicates the threat is still active and is appearing across multiple VMs in the same broadcast domain (suggesting lateral movement or propagation within that Layer 2 segment). Since quarantine of a single VM did not stop the threat, the appropriate next step is to broaden containment by isolating the affected subnet / network segment to prevent further spread.

The Sybex CySA+ Study Guide emphasizes that after identifying an incident in progress, responders should move into containment and that containment activities include segmentation and isolation:

Exact extract (Sybex Study Guide):

“After identifying a potential incident in progress, responders should take immediate action to contain the damage… Potential containment activities include network segmentation, isolation, and removal of affected systems.”

It also explains how segmentation (quarantine VLAN) is used to contain compromised systems and protect other systems:

Exact extract (Sybex Study Guide):

“During the early stages of an incident… [responders] built a separate virtual LAN (VLAN) to contain those systems… Putting the systems on this network segment provides some degree of isolation…”

Because the activity is occurring across the broadcast domain, isolating just one VM isn’t enough; the team should continue containment by isolating the subnet/segment where the issue is spreading (Option D). Moving to eradication (Option C) before containment is effective risks continued spread and loss of control.

Command-and-control (C2) beaconing involves compromised systems communicating with an attacker’s server at regular intervals, often using HTTPS to blend in with legitimate traffic. This is indicative of a potential compromise where malware communicates back to a command center. The persistent nature of the connections after hours and throughout the day suggests automated beaconing, which is a tell-tale sign of C2 activity. According to CompTIA CySA+, this type of activity should raise immediate suspicion and warrants further investigation and containment. While options B, C, D, and E might indicate other issues, they do not fit the pattern described as well as option A.

A vulnerability scan is a process of identifying and assessing the security weaknesses of a system or network. A vulnerability scan can help a security analyst to effectively identify the most security risks associated with a locally hosted server, such as missing patches, misconfigurations, outdated software, or exposed services. A vulnerability scan can also provide recommendations on how to remediate the identified vulnerabilities and improve the security posture of the server12 References: 1: What is a Vulnerability Scan? | Definition and Examples 2: Securing a server: risks, challenges and best practices - Vaadata

The correct answer is D. The remediation was technically successful, but it took place during five business hours on a sales application. That likely caused business process interruption and lost sales. The problem was not the patch itself; the problem was poor change scheduling and communication.

Exact supporting extract: the Sybex CySA+ Study Guide states that changes can be disruptive and that the timing of changes should be carefully coordinated. It also explains that maintenance windows usually occur during evenings, weekends, or other periods when business activity is low.

The official CySA+ objectives also list patching, business process interruption, degrading functionality, SLAs, SLOs, and stakeholder communication as key vulnerability management reporting and communication concerns.

Why the other options are incorrect:

A is incorrect because this was avoidable operational loss caused by poor scheduling.

B is incorrect because the issue is not specifically board notification by the CIO.

C is incorrect because a penetration test is not required before every patch.

D is correct because a properly scheduled and communicated maintenance window should reduce business impact.

Key pair authentication is a method of using a public and private key to securely access cloud resources, such as downloading the configuration of assets from a cloud tenancy. Key pair authentication is more secure than user and password or PAM, and does not require an additional factor like MFA.

EDR stands for Endpoint Detection and Response, which is a tool that collects and aggregates data from various endpoints, such as laptops, servers, or mobile devices. EDR helps analysts monitor, detect, and respond to threats and incidents on the endpoints. EDR is more suitable than DLP (Data Loss Prevention), NAC (Network Access Control), or NIDS (Network Intrusion Detection System) for data collection and aggregation from endpoints.

Because the system is mission critical and there is no patch and no vendor support, the best risk-reduction approach is to implement compensating controls. Compensating controls are specifically recommended when immediate remediation is not possible, and for legacy systems where patches may not exist.

The Sybex CySA+ Study Guide states this directly:

Exact extract (Sybex Study Guide): “Legacy systems may not have patches available, meaning that compensating controls may be the only option available.”

Secbay Press also explains that legacy systems may lack vendor support/updates and that miti gation strategies like compensating controls or isolation are essential to reduce risk:

Exact extract (Secbay Press): “Legacy systems may lack vendor support and updates, making mitigation strategies essential… Implement specific mitigation strategies for legacy systems, such as compensating controls or isolation.”

And Secbay provides a legacy-system compensating control case study showing exactly the kinds of controls mentioned in option D—segmentation/isolation, access controls, and enhanced monitoring/continuous monitoring:

Exact extract (Secbay Press): “Selected compensating controls, such as network segmentation, intrusion detection systems, and enhanced monitoring, to mitigate the risks…”

Why the other options are not “best” given the constraints:

A (Decommission immediately): may be ideal long-term, but conflicts with “mission critical” (and “immediately” is often unrealistic for business operations).

B (Block inbound/allow outbound): helps somewhat but is incomplete and can still allow command-and-control or exfiltration outbound; also doesn’t address restricted admin access/monitoring comprehensively.

C (WAF): useful only if this is specifically a web application exposure; the scenario says “legacy system” broadly. Compensating controls are the most complete and universally applicable choice.

References (CompTIA CySA+ CS0-003 documents / study guides used):

Chapple/Seidl, CompTIA CySA+ Study Guide (CS0-003): legacy systems may have no patches; compensating controls may be the only option

Secbay Press, CompTIA CySA+ Exam Prep Guide (CS0-003): legacy systems lack support/updates; use compensating controls or isolation

Secbay Press, CompTIA CySA+ Exam Prep Guide (CS0-003): compensating controls for legacy systems include segmentation/isolation and enhanced/continuous monitoring

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

This is because scanning without admin privileges can limit the scope and accuracy of the vulnerability scan, and potentially miss some critical vulnerabilities that require higher privileges to detect. According to the OWASP Vulnerability Management Guide1, “scanning without administrative privileges will result in a large number of false negatives and an incomplete scan”. Therefore, the analyst should recommend addressing this issue to ensure potential vulnerabilities are identified.

The Diamond Model of Intrusion Analysis focuses on understanding the relationships between the adversary, their capabilities, infrastructure, and victim. It provides a structured approach to examining how attackers exploit information assets. According to CompTIA CySA+, this model is valuable for detailing attack patterns and understanding the infrastructure attackers use. The other options, like Structured Threat Information Expression (A) and OWASP Testing Guide (B), address threat data sharing and web application testing, respectively, while the Open Source Security Testing Methodology Manual (OSSTMM) (C) covers general security testing procedures.

The vulnerability is network based is the correct attribute that describes this vulnerability, as it can be inferred from the CVSS string. CVSS stands for Common Vulnerability Scoring System, which is a framework that assigns numerical scores and ratings to vulnerabilities based on their characteristics and severity. The CVSS string consists of several metrics that define different aspects of the vulnerability, such as the attack vector, the attack complexity, the privileges required, the user interaction, the scope, and the impact on confidentiality, integrity and availability. The first metric in the CVSS string is the attack vector (AV), which indicates how the vulnerability can be exploited. The value of AV in this case is N, which stands for network. This means that the vulnerability can be exploited remotely over a network connection, without physical or logical access to the target system. Therefore, the vulnerability is network based. Official References:

https://partners.comptia.org/docs/default-source/resources/comptia-cysa-cs0-002-exam-objectives

https://www.comptia.org/certifications/cybersecurity-analyst

https://packitforwarding.com/index.php/2019/01/10/comptia-cysa-common-vulnerability-scoring-system-cvss/

Deduplication is a process that involves removing any duplicate or redundant data or information from a data set or source. Deduplication can help consolidate several threat intelligence feeds by eliminating any overlapping or repeated indicators of compromise (IoCs), alerts, reports, or recommendations. Deduplication can also help reduce the volume and complexity of threat intelligence data, as well as improve its quality, accuracy, or relevance.