Free Practice Questions for the CompTIA CySA+ CS0-004 Exam (2026 Updated)

Compensating controls are appropriate when the preferred remediation cannot currently be implemented but the organization must still reduce exposure. A mission-critical system with an unpatched vulnerability for which no vendor patch exists is a classic example. The system cannot simply be removed from service because the business requires it, and conventional patching is unavailable.

The organization may therefore deploy alternative controls such as network segmentation, restrictive firewall rules, application allowlisting, disabling unnecessary services, enhanced monitoring, IPS signatures, access restrictions, or isolation of affected functionality. These measures do not eliminate the underlying defect; instead, they reduce the probability or impact of exploitation while a permanent solution is developed.

NIST's control framework is designed to allow security controls to be selected and tailored according to organizational mission requirements and risk, supporting the broader principle that organizations may apply appropriate alternative safeguards when operational constraints exist.

Option B requires no compensating control because remediation has already occurred. Option C describes a vulnerability that is not applicable to the organization's systems. Option D represents a false positive and therefore does not constitute an actual exposure requiring mitigation.

Study Guide Reference: Vulnerability Management → Mitigation → Compensating Controls → Patch Availability → Mission-Critical Systems → Segmentation and Monitoring.

AI usage policies establish organizational boundaries for how artificial intelligence systems may be selected, accessed, configured, and used. They allow an organization to obtain operational benefits from AI while controlling risks involving confidential information, intellectual property, regulated data, model outputs, external AI services, and inappropriate automation. A strong policy can define approved platforms, prohibited data categories, validation requirements, human oversight, retention rules, acceptable use, and escalation procedures.

Prompt engineering is a technical method for constructing inputs that produce more useful model responses. It can improve output quality but does not establish enterprise-wide safeguards for protecting business objectives or sensitive information. A non-disclosure agreement establishes contractual confidentiality obligations between parties; it cannot govern the full technical and operational use of AI systems. An incident response policy determines how security incidents are managed and escalated, but it is reactive and not designed to establish routine AI governance.

CS0-004 explicitly addresses AI within Security Operations. The objectives identify AI risks including hallucinations, data exposure, model poisoning, and malicious prompts and identify governance considerations including legal or regulatory compliance and AI usage policies . AI use cases include log analysis, artifact comparison, incident investigation, event correlation, and automation.

Study Guide Reference: Security Operations → AI in Security Operations → AI Risks → Governance → AI Usage Policies → Data Protection.

Clearly defined roles and responsibilities are foundational to incident-response preparation because responders must know in advance who has authority to make decisions and who performs specific technical, management, legal, communications, and recovery functions. Attempting to determine ownership while an active compromise is developing introduces delays, duplicated effort, communication failures, and potentially conflicting actions.

Preparation should define escalation paths, decision-making authority, contact mechanisms, incident leadership, technical responsibilities, evidence-management responsibilities, and coordination with business, legal, privacy, communications, and external parties where applicable. NIST's current incident-response guidance emphasizes preparation across organizational risk-management activities so organizations can respond and recover efficiently when incidents occur.

An after-action report is produced after an incident and documents the event, response actions, recovery, and lessons learned. Data-integrity validation is important during evidence analysis and recovery but is not the primary organizational foundation of preparation. Chain of custody must be established when evidence is collected and transferred, particularly where legal proceedings may occur, but it represents one procedure within a broader incident-response capability.

Without predefined ownership, even technically sound procedures may fail operationally.

Study Guide Reference: Incident Response and Management → Preparation → Incident Response Plan → Roles and Responsibilities → Escalation → Communication → Authority and Coordination.

The recurring weekly conference call is intended to manage and facilitate team coordination . The analyst's stated objectives are to understand workflow processes and the capabilities of the engineers participating in the cybersecurity improvement project. Regular coordination meetings provide a structured mechanism for sharing operational updates, clarifying responsibilities, identifying dependencies, communicating blockers, aligning technical activities, and understanding which personnel possess the expertise required for particular tasks.

Nothing in the scenario indicates an incident requiring formal incident-response training. Training would normally involve exercises, tabletop scenarios, simulations, procedures, or instruction designed to build response capability. There is also no vendor involvement, so a vendor information session would not satisfy the stated objective. Likewise, no customer request is identified.

The distinguishing clue is the combination of a cross-functional task force, workflow understanding, skills visibility, and recurring communication . These elements support internal project coordination rather than external communication or formal instruction.

Within CySA+, reporting and communication extends beyond writing final reports. Analysts must communicate effectively with technical teams, coordinate activities with relevant stakeholders, provide appropriate status information, and ensure security work is understood and actionable across organizational functions.

Study Guide Reference: Reporting and Communication → Stakeholder Communication → Team Coordination → Roles and Responsibilities → Workflow Management → Cross-Functional Collaboration.

Prowler is designed for cloud security assessment, configuration review, and compliance evaluation, which directly meets the requirement to establish cloud-security baselines. The project's official repository describes Prowler as an open-source cloud security platform that automates security and compliance assessments across cloud environments and provides extensive security checks, reporting, and remediation guidance.

Baseline assessments establish an expected security posture against which subsequent configurations and changes can be evaluated. Prowler can examine cloud settings such as identity permissions, logging, encryption, public exposure, network controls, storage configuration, and service-specific security features. This allows the vulnerability-management team to identify deviations from security and compliance expectations.

Metasploit is an exploitation framework used primarily for penetration testing and validation of exploitable weaknesses. Maltego is an information-gathering and relationship-mapping platform frequently associated with OSINT and infrastructure reconnaissance. MITRE CALDERA is an adversary-emulation platform used to exercise defensive controls using automated attack techniques.

The term “cloud environment” combined with “security baselines” points directly toward a cloud posture and compliance assessment tool rather than exploitation, OSINT, or adversary simulation.

Study Guide Reference: Vulnerability Management → Cloud Assessments → Prowler → Security Baselines → Configuration Auditing → Compliance Checks → Cloud Security Posture.

The -r file.pcap argument instructs TShark to read packets from the specified capture file, while -Y applies a Wireshark display filter . The expression "http or udp" therefore displays packets recognized as HTTP or packets using UDP.

Traditional HTTP traffic is unencrypted and can be dissected directly as HTTP. HTTPS normally carries HTTP inside TLS encryption and therefore is not displayed merely because the filter specifies http. DNS commonly operates over UDP, particularly for standard queries and responses, so ordinary DNS traffic satisfies the udp portion of the expression. Consequently, B is the best answer in the context of the available choices.

A technical distinction is important: the expression does not mean “HTTP or DNS specifically.” The udp portion matches UDP traffic generally, which can include protocols other than DNS. Nevertheless, within the examination scenario, the intended comparison is plaintext HTTP versus encrypted HTTPS together with standard UDP-based DNS.

Wireshark's documentation distinguishes display filters from capture filters, and TShark is the command-line network traffic analyzer within the Wireshark suite. CS0-004 places packet-analysis capabilities within Security Operations.

Study Guide Reference: Security Operations → Packet Analysis → Wireshark/TShark → PCAP Analysis → Display Filters → HTTP, UDP, and DNS.

Eradication addresses the root causes and malicious mechanisms that allow an attacker to remain inside the environment. Typical eradication actions include deleting malware, removing persistence mechanisms, disabling unauthorized accounts, resetting compromised credentials, eliminating malicious scheduled tasks or services, correcting exploited vulnerabilities, and rebuilding systems when trust cannot be restored.

This differs fundamentally from containment. Containment is intended to limit immediate damage or prevent further spread , such as isolating an infected workstation, blocking an IP address, disabling a network segment, or temporarily suspending an account. These measures can interrupt attacker activity, but they do not necessarily remove the underlying foothold. Microsoft security architecture guidance similarly distinguishes containment from eradication and describes eradication procedures as completely removing the threat from the environment.

Detection identifies that suspicious or malicious activity exists; it does not remove access. Denial of service is an attack or availability condition rather than a recognized incident-response phase.

Therefore, if the examination asks which phase permanently removes the adversary's access , the correct answer is eradication because this is where attacker persistence and the enabling compromise are eliminated before normal operations are fully restored.

Study Guide Reference: Incident Response and Management → Containment → Eradication → Persistence Removal → Credential Reset → Malware Removal → Vulnerability Remediation.

A tabletop exercise is the most appropriate method because the objective is to collaboratively validate an updated incident-response plan with relevant stakeholders. Tabletop exercises are discussion-driven simulations in which participants work through a realistic incident scenario, explain their expected actions, identify dependencies, evaluate communication paths, and expose procedural or organizational gaps without performing disruptive live attacks.

CISA states that tabletop exercises are used to validate or improve understanding of plans and procedures, rehearse concepts, assess incident-response and recovery requirements, and identify areas requiring improvement. CISA also provides Tabletop Exercise Packages specifically to help stakeholders conduct collaborative exercises and organizational discussions.

A red-team event involves active adversary simulation and focuses primarily on testing defensive capabilities against realistic attacker behavior. A penetration test evaluates exploitable technical weaknesses. Security awareness training teaches users security knowledge but does not collaboratively validate incident-response roles, escalation paths, communications, and decision-making.

Because the manager recently made significant plan updates , a tabletop exercise provides a controlled mechanism for all stakeholders to determine whether those procedures actually function as intended before a real incident occurs.

Study Guide Reference: Incident Response and Management → Preparation → Incident Response Plan → Tabletop Exercises → Stakeholder Coordination → Testing Plans and Procedures.

The organization remains in the eradication phase because malicious artifacts are still being removed from affected systems and the environment has not yet reached a trusted state suitable for complete restoration. The phrase “removing malware from some of the affected hosts” indicates that responders are actively eliminating the threat across the compromised estate rather than merely observing or documenting it.

Eradication addresses malware, attacker persistence, exploited vulnerabilities, unauthorized accounts, malicious configurations, compromised credentials, and other mechanisms that could permit reinfection or renewed access. Only after responders have sufficiently eliminated those causes should affected resources progress fully into recovery and return to normal operation. NIST's current incident-response model identifies containment, eradication, and recovery as related but distinct activities and emphasizes restoring assets only after appropriate incident handling has occurred.

Detection would have occurred when the incident was initially discovered. Analysis determines scope, cause, and impact. Preparation takes place before incidents by establishing plans, tools, procedures, and capabilities. Post-incident activities occur after response and restoration and focus on organizational improvement.

The two-week duration does not determine the phase. The activity being performed does : continued removal of malware indicates eradication.

Study Guide Reference: Incident Response and Management → Containment → Eradication → Malware Removal → Persistence Removal → System Validation → Recovery.

During an active cybersecurity incident, responders must assume that systems associated with the compromise may no longer provide trustworthy confidentiality or integrity until their status has been established. If the incident could involve the organization's email infrastructure, discussing response strategy, investigative findings, affected assets, or containment actions through corporate email could unintentionally provide the attacker with intelligence about the organization's response.

Therefore, the email system may be compromised is the strongest explanation. Incident-response communication plans should define approved communication methods, relevant stakeholders, escalation paths, and alternative communication channels so responders can continue coordinating when ordinary enterprise systems are unavailable or untrusted. NIST's current incident-response guidance emphasizes integrating communication and stakeholder coordination throughout response activities.

Option C is too broad. Modern email commonly uses transport encryption, although encryption alone would not make a compromised mailbox or server trustworthy. Option D concerns public-relations coordination but does not explain why email itself should be avoided. Option A describes a specific gateway vulnerability that the scenario does not establish.

The core principle is out-of-band communication : when normal communication infrastructure may be under attacker control, responders should use a previously approved independent channel.

Study Guide Reference: Reporting and Communication → Incident Communications → Communication Plan → Out-of-Band Communications → Stakeholder Coordination → Compromised Communication Channels.

Encryption at rest primarily protects the confidentiality of stored information when an unauthorized party obtains physical or logical access to the storage medium. This is particularly important for laptops because portable devices can be lost or stolen, giving an attacker possession of the disk outside the organization's normal network and endpoint protections.

NIST guidance on storage encryption specifically addresses laptops and other end-user devices and explains that storage encryption combines encryption and authentication to restrict unauthorized access to stored information. NIST further notes that threats involving lost or stolen end-user devices can expose information to unauthorized parties.

Encryption does not inherently prevent an authenticated and authorized user from copying information while the system is unlocked; data loss prevention controls are more directly suited to that objective. Regulatory requirements may mandate encryption in some environments, but compliance is an external requirement rather than the fundamental security reason encryption at rest exists. Option D confuses confidentiality with integrity and network protection. Encryption of data stored on a laptop is not primarily intended to validate whether network data has been modified.

The examination concept is the CIA triad: encryption primarily supports confidentiality , especially when physical possession of the storage device is lost.

Study Guide Reference: Security Operations → Data Protection → Encryption at Rest → Full-Disk Encryption → Confidentiality → Lost/Stolen Endpoint Protection.

Tactics, techniques, and procedures (TTPs) occupy the highest level of the Pyramid of Pain because they represent the adversary's operational behavior rather than disposable technical artifacts. The model describes how different types of defensive indicators impose progressively greater disruption on an attacker when defenders successfully detect and deny them.

An IP address is comparatively easy to replace by changing hosting infrastructure, using a proxy, acquiring a new virtual server, or moving command-and-control services. Domain names similarly can be registered or replaced with relatively limited operational impact. Tools create greater difficulty because replacing or substantially modifying malware, frameworks, or utilities requires more attacker effort.

TTPs are significantly more costly to change because they encompass how the adversary conducts operations : the sequence and methods used for initial access, persistence, credential access, privilege escalation, lateral movement, command and control, and other objectives. Forcing attackers to change established behavior may require retraining personnel, redesigning operational processes, developing new capabilities, or adopting unfamiliar techniques.

This is why behavioral detection is strategically valuable. Indicators such as hashes and IP addresses may disappear quickly, while detections focused on adversary behavior can remain useful across multiple toolsets and infrastructure changes.

Study Guide Reference: Security Operations → Threat Intelligence → Pyramid of Pain → TTPs → Behavioral Indicators → Adversary Tracking.

An after-action report (AAR) is the most comprehensive document associated with a closed incident because it consolidates the incident itself, the response activities performed, recovery actions, outcomes, deficiencies, and lessons identified during the event. NIST Cybersecurity Framework guidance specifically calls for preparing an after-action report that documents the incident, response and recovery activities, and lessons learned.

A lessons-learned document focuses primarily on what worked, what failed, and what should be improved. Those observations are important, but they represent only one component of a complete post-incident record. Root cause analysis has a narrower technical purpose: determining the fundamental condition that permitted the incident to occur or progress. A situation report is generally produced while an incident is ongoing to communicate current status, impact, actions, and outstanding issues.

An AAR is broader because it can incorporate the timeline, technical findings, containment and eradication actions, recovery results, stakeholder performance, root cause, lessons learned, and assigned corrective actions. NIST exercise guidance likewise treats lessons learned as information that becomes part of an after-action report.

Study Guide Reference: Reporting and Communication → Post-Incident Reporting → After-Action Reports → Lessons Learned → Root Cause Analysis → Corrective Actions.

CyberChef is the most appropriate option because the task involves parsing and extracting structured indicators from unstructured text , rather than inspecting network traffic or managing a threat-intelligence repository. CyberChef provides operations for text manipulation, pattern matching, regular expressions, decoding, extraction, and transformation. An analyst can therefore feed the document into CyberChef and identify IPv4 address patterns without manually reviewing potentially thousands of characters.

Wireshark is primarily a packet-analysis platform. It would be appropriate if the analyst needed to inspect packets from a PCAP or live network capture, but the scenario provides a text document. Zeek is a network security monitoring and traffic-analysis framework that converts network activity into structured logs; it is similarly unnecessary for static textual extraction. OpenCTI is a threat-intelligence platform designed to organize, correlate, and manage intelligence objects and relationships. It could store the resulting IoCs after extraction, but it is not the most efficient tool for extracting IPv4 strings from raw text.

The official CS0-004 objectives identify CyberChef under decoding/parsing tools , while Wireshark and Zeek are classified under packet analysis and OpenCTI under threat-intelligence platforms.

Study Guide Reference: Security Operations → Tools for Malicious-Activity Analysis → Decoding/Parsing → CyberChef → Pattern Recognition/Regular Expressions → IoC Analysis.

Option D applies the correct packet-filtering logic to isolate DNS-related traffic associated with the suspected server . The -r suspicious.pcap option directs tcpdump to read packets from the existing PCAP rather than capture live traffic. The expression port 53 and host 10.213.4.27 then limits output to packets involving the specified system and DNS's conventional port 53.

This is directly relevant to suspected DNS exfiltration. Attackers can encode data within DNS queries or responses, including unusually long subdomains or other manipulated DNS fields. Isolating the target's port 53 traffic dramatically reduces the dataset and allows the analyst to examine relevant queries and responses for encoded or anomalous information.

strings suspicious.pcap | grep treats the capture primarily as raw printable data and does not accurately perform protocol-aware packet filtering. The Zeek option searches file.log, which is focused on files observed in network traffic and is not the most direct location for DNS-query analysis. The Snort syntax shown is also inappropriate for the required extraction workflow.

The essential skill is translating an investigative hypothesis— possible DNS exfiltration by a known host —into a precise PCAP filter.

Study Guide Reference: Security Operations → Network Traffic Analysis → Full Packet Capture → tcpdump → BPF Filters → DNS Analysis → Data Exfiltration Detection.

A paid, subscription-based threat intelligence service is best classified as closed-source intelligence because access is restricted to authorized subscribers rather than being freely available to the public. Commercial threat-intelligence providers typically collect, analyze, correlate, and curate indicators and adversary information before distributing that intelligence through authenticated portals, APIs, or feeds.

NIST identifies several external intelligence-source categories, including open-source repositories, commercial threat feeds, and external information-sharing partners . A commercial feed relevant to a company's specific industry may provide higher-context intelligence regarding threat actors, infrastructure, malware, vulnerabilities, campaigns, and indicators affecting that vertical.

OSINT, by contrast, originates from publicly accessible sources and normally does not require restricted subscription access. Threat mapping is the activity of associating adversary behavior or intelligence with infrastructure, campaigns, frameworks, or organizational assets. Threat modeling is a structured process used to identify potential threats and weaknesses in systems or applications; it is not an intelligence-source classification.

The examination clue is “paid subscription.” Restricted commercial access distinguishes the feed from publicly obtainable OSINT.

Study Guide Reference: Security Operations → Threat Intelligence → Intelligence Sources → Open-Source Intelligence → Closed/Commercial Intelligence → Industry-Specific Threat Feeds.

The scenario describes an AI hallucination , commonly termed confabulation in formal AI risk-management literature. The defining characteristic is that the model produces information that appears plausible but is factually incorrect or unsupported. Here, the AI system introduces events that never occurred, contaminating the event-correlation process and potentially causing analysts to reach incorrect conclusions.

NIST's Generative AI Profile identifies confabulation as the production of confidently stated but erroneous or false content and treats it as an AI risk that requires verification and monitoring. NIST cybersecurity guidance also recognizes hallucination and confabulation as risks to information accuracy when AI is incorporated into cybersecurity workflows.

Data exposure would involve unauthorized disclosure of confidential or sensitive information. A malicious prompt involves intentionally crafted input designed to influence model behavior or bypass restrictions. Model poisoning occurs when an adversary manipulates training or model-related data to corrupt the system's behavior. None of these conditions is required in the scenario; the critical evidence is fabrication of nonexistent events.

Security analysts therefore must treat AI-generated correlation as analytical assistance rather than unquestioned evidence and validate important conclusions against authoritative logs and telemetry.

Study Guide Reference: Security Operations → Artificial Intelligence → AI Risks → Hallucinations → Data Exposure → Malicious Prompts → Model Poisoning → Human Validation.

Option C represents the appropriate YARA matching approach because the analyst is searching for an encoded representation of ActiveMime , not necessarily the literal plaintext string. The grep -rail ActiveMime * command performs a case-insensitive recursive search for the textual value ActiveMime. If the payload contains that value encoded—commonly through Base64 or another transformed representation—the literal byte sequence will not be present and grep will therefore fail to identify it.

YARA is designed specifically for pattern-based identification of malicious or suspicious content. Its string modifiers support encoded representations. YARA's official documentation states that the base64 modifier searches for Base64-encoded forms of a specified string, while base64wide extends this behavior to wide-character representations. Therefore, a rule constructed to detect the encoded form of ActiveMime can identify relevant documents without requiring the literal plaintext sequence to occur in the file.

The essential examination concept is the distinction between literal text searching and malware-oriented encoded-pattern matching . Rules that search only for ordinary ASCII ActiveMime reproduce the limitation of the unsuccessful grep command.

Study Guide Reference: Security Operations → Malware Analysis → YARA → Signature/Pattern Matching → Encoded Content → Base64/Base64wide → File Analysis.

YARA is specifically designed to identify and classify suspicious or malicious files through pattern-based rules . A YARA rule can contain textual strings, hexadecimal byte sequences, regular expressions, metadata, file characteristics, and Boolean conditions. This makes YARA particularly effective when an analyst already has a binary specimen on an isolated analysis system and needs to determine whether it contains patterns associated with malware.

The official YARA documentation describes YARA as a tool for helping malware researchers identify and classify malware samples using textual and binary patterns. Rules consist primarily of strings and logical conditions that determine whether a file matches the defined characteristics.

The strings utility can reveal printable characters embedded within a binary and is useful during preliminary static analysis, but it does not itself classify the file against structured malware-detection signatures. VirusTotal can perform multi-engine analysis, but submitting a potentially sensitive binary from an isolated environment to an external service may be inappropriate and is unnecessary when local YARA detection is available. WHOIS provides registration information about internet resources and has no direct binary-malware detection capability.

Study Guide Reference: Security Operations → Malware Analysis → Static Analysis → YARA → Signature and Pattern Matching → Binary/File Analysis.

The analyst should first establish a legal hold because the suspected breach involves personnel records and evidence that may become relevant to regulatory, disciplinary, civil, or other legal proceedings. A legal hold prevents potentially relevant information from being deleted, overwritten, modified, rotated out under normal retention schedules, or otherwise destroyed before the organization's legal and investigative obligations are understood.

Preservation must precede destructive or potentially evidence-altering actions. NIST describes digital forensics as retrieving, storing, and analyzing electronic information while ensuring that evidence is captured reliably without alteration. RFC 3227 similarly emphasizes preserving evidence, following proper collection procedures, documenting handling, and maintaining chain of custody.

Log correlation and timeline construction are important investigative activities, but they should occur after preservation requirements have been established. Resetting credentials may subsequently be required for containment, but the scenario first raises an evidence-preservation obligation. Restoring files from backup would be especially premature because it could alter timestamps, overwrite artifacts, or otherwise complicate forensic analysis.

The examination principle is therefore preserve first when legal implications are reasonably foreseeable; analyze and remediate afterward under controlled procedures .

Study Guide Reference: Incident Response and Management → Evidence Acquisition → Legal Hold → Evidence Preservation → Chain of Custody → Timeline Analysis → Regulatory/Legal Considerations.

The original scan fails because Nmap's host-discovery process concludes that the target appears offline before conducting the intended full port scan. Option C adds -Pn , instructing Nmap to skip normal host discovery and proceed with scanning the target as though it is online. The -p- option then instructs Nmap to test the complete TCP port range rather than only its default set.

This is appropriate when a live host does not respond to discovery probes because ICMP echo traffic or other discovery packets may be filtered by firewalls, host-based controls, or network policy. A system can therefore appear “down” to Nmap's discovery phase while still exposing reachable TCP services.

Option B uses -sn, which performs host discovery without a port scan and therefore contradicts the requirement. Option A scans only a limited set of explicitly identified ports and includes unrelated functionality. Option D unnecessarily changes the scope to an entire /24, performs operating-system detection and DNS resolution, and invokes an SSL cipher script; none of those modifications addresses the immediate host-discovery problem.

Study Guide Reference: Vulnerability Management → Nmap → Host Discovery → -Pn → Full Port Scanning -p- → Firewall/ICMP Filtering → Scan Troubleshooting.