CompTIA CS0-003 Practice Test

Correct Answer:

Routing table:

In incident response, investigators follow the Order of Volatility (OoV), which is a core concept emphasized in the CompTIA CySA+ CS0-003 Official Study Guide. The goal is to collect the most volatile data first—information that is likely to disappear if the system is shut down, rebooted, or isolated. The routing table is a prime example of volatile data stored in memory (RAM). It holds the current paths used for network communication, which can provide crucial evidence about active connections, potential lateral movement, or exfiltration routes used by an attacker. Since this data is lost when the server is powered off or disconnected, it must be captured before any isolation or shutdown occurs.

Incorrect Answers Explained:

Hard disk:This is non-volatile storage, meaning the data on it remains intact even after the system is powered down. While it may contain critical evidence such as logs or malware binaries, it is not time-sensitive and does not need to be collected first.

Primary boot partition: Like the hard disk, this contains static data related to the operating system and startup configuration. It does not change frequently during operations and is not lost during shutdown, so it can be captured later in the evidence collection process.

Malicious tiles:This is a vague term and not clearly defined in CompTIA materials. If it refers to files or interface elements related to malware, they reside on disk and are not volatile. Again, these can be collected after volatile memory.

Static IP address: A static IP is part of the system’s configuration settings and does not change dynamically. This information can be retrieved from configuration files or network settings even after shutdown, so it’s not critical to collect first.

Reference:

CompTIA CySA+ CS0-003 Official Study Guide, under the topic of “Order of Volatility” in the Incident Response domain. This section emphasizes prioritizing the collection of volatile data (such as network session details and routing tables) before non-volatile sources like disk or configuration data.

Correct Answer:

Acquire a bit-level image of the affected workstation:
This step is crucial for preserving forensic evidence. A bit-level image is an exact copy of the entire contents of a storage device, including deleted files, slack space, and system artifacts. It allows investigators to:

Analyze the ransomware payload and its behavior

Identify indicators of compromise (IoCs)

Preserve the integrity of evidence for legal or regulatory purposes

According to CompTIA CySA+ CS0-003 best practices, imaging should be done before any remediation to avoid altering or destroying critical data.

Incorrect Answer:

Wipe the computer and reinstall software:
While this may eventually be necessary, doing so before imaging would destroy valuable forensic evidence. It’s a recovery step, not an investigative one.

Shut down the email server and quarantine it from the network:
This is an overreaction unless there’s evidence the email server itself is compromised. The attack originated from a phishing email, not necessarily from the server.

Search for other mail users who have received the same file:
This is a valid follow-up step for containment and awareness, but it should come after securing and preserving evidence from the initial infection.

Explanation:

The question asks for the first action a security analyst should take to determine precisely what happened during a security incident on a server that occurred over an extended holiday break, given that the incident was reported timely, and the server is up to date with appropriate auditing and logging. Cloning the virtual server for forensic analysis is the most critical first step, as it creates a forensically sound copy of the server’s state, preserving all evidence (e.g., logs, memory, file system) for detailed investigation without altering the original system. This aligns with the CS0-003 exam’s Incident Response and Management (Domain 3) and Security Operations (Domain 1) objectives, which emphasize forensic best practices and evidence preservation in incident response.

Why A is Correct:

Cloning for Forensics:
Cloning a virtual server (e.g., creating a snapshot or disk image in a virtualized environment like VMware or Hyper-V) captures the entire system state, including volatile data (e.g., memory, running processes) and non-volatile data (e.g., logs, files). This ensures evidence is preserved for analysis to determine precisely what happened (e.g., attack vector, malware, data accessed).

Preserving Evidence:
Forensic best practices (e.g., NIST SP 800-86) prioritize preserving evidence before interacting with a compromised system, as actions like logging in or shutting down can alter or destroy critical data (e.g., memory-resident malware, temporary files).

Healthcare Context:
In a healthcare organization (per prior questions), preserving evidence is crucial for HIPAA compliance, as the incident may involve PHI, requiring detailed analysis for breach reporting and regulatory compliance. CS0-003 Alignment: Domain 3 emphasizes evidence collection and preservation during incident response, often tested via performance-based questions (PBQs), while Domain 1 supports securing critical systems through proper forensic procedures.

Why Other Options Are Incorrect:

B. Log in to the affected server and begin analysis of the logs:
Reason: Logging into the server risks altering its state (e.g., modifying timestamps, overwriting memory, or triggering malware). While the server has auditing and logging enabled, direct access could compromise evidence integrity. Cloning first ensures a pristine copy for analysis, making this a later step.

C. Restore from the last known-good backup to confirm there was no loss of connectivity:
Reason: Restoring from a backup is part of the Recovery phase, not investigation. It erases the compromised state, destroying evidence needed to determine what happened. Connectivity loss is irrelevant to the CISO’s goal of understanding the incident, making this premature and incorrect.

D. Shut down the affected server immediately:
Reason: Shutting down the server risks losing volatile data (e.g., memory contents, active processes, network connections), which is critical for understanding the incident (e.g., identifying ransomware or C2 servers). While shutdown may be part of containment, cloning preserves evidence first, especially in a virtualized environment where snapshots are non-disruptive.

Additional Context:

Incident Context:
The incident occurred during a holiday break, suggesting delayed detection, but timely reporting indicates monitoring was active. The server’s up-to-date status and logging suggest robust evidence (e.g., /var/log/syslog, Windows Event Logs) is available for analysis.

Cloning Process:
Take a snapshot or clone the virtual machine (e.g., vmkfstools -i source.vmdk clone.vmdk in VMware).
Use forensic tools (e.g., FTK Imager, Autopsy) on the clone to analyze logs, memory, and files.
Calculate hashes (e.g., sha256sum clone.vmdk) to ensure integrity.

Next Steps:
After cloning, analyze the image for IOCs (e.g., malware, unauthorized access), review logs (e.g., Event ID 4624 for logins), and correlate with SIEM data to reconstruct the incident timeline.

CS0-003 Relevance:
Domain 3 tests forensic procedures, prioritizing evidence preservation, while Domain 1 emphasizes securing systems during incidents, both favoring cloning for analysis.

Reference:
CompTIA CySA+ (CS0-003) Exam Objectives, Domains 1 (Security Operations) and 3 (Incident Response and Management),
covering forensic evidence collection and incident response.
CompTIA CySA+ Study Guide: Exam CS0-003 by Chapple and Seidl, discussing forensic analysis for virtualized environments.

Explanation:

The question asks which attribute correctly describes a vulnerability based on the provided CVSS 3.0 vector string: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. By analyzing the CVSS metrics, the vulnerability is network based (AV:N) is the correct attribute, as it indicates the vulnerability can be exploited over a network, aligning with the CS0-003 exam’s Vulnerability Management (Domain 2) objective, which emphasizes understanding CVSS metrics for assessing vulnerabilities. CVSS 3.0 Vector Analysis:

The CVSS 3.0 string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H breaks down as follows:

AV:N (Attack Vector: Network): The vulnerability is exploitable remotely over a network (e.g., internet or intranet).

AC:L (Attack Complexity: Low): The attack is straightforward, requiring minimal skill or conditions.

PR:N (Privileges Required: None): No authentication or privileges are needed to exploit.

UI:N (User Interaction: None): No user interaction (e.g., clicking a link) is required.

S:U (Scope: Unchanged): The impact is confined to the vulnerable component (e.g., the targeted system).

C:H/I:H/A:H (Confidentiality/Integrity/Availability: High): The vulnerability severely impacts confidentiality (data disclosure), integrity (data modification), and availability (system disruption).

Evaluation of Options:

A. A user is required to exploit this vulnerability:
Reason: The vector includes UI:N (User Interaction: None), meaning no user interaction is required for exploitation. This option is incorrect.

B. The vulnerability is network based:
Reason: The vector specifies AV:N (Attack Vector: Network), indicating the vulnerability can be exploited remotely over a network, such as an internet-facing server. This matches the description and is correct.

C. The vulnerability does not affect confidentiality:
Reason: The vector shows C:H (Confidentiality: High), indicating a severe impact on confidentiality (e.g., sensitive data like PHI in a healthcare context could be exposed). This option is incorrect.

D. The complexity to exploit the vulnerability is high:
Reason: The vector includes AC:L (Attack Complexity: Low), meaning the attack is easy to execute with minimal barriers.
This option is incorrect.

Additional Context:

Vulnerability Severity: The metrics (AV:N, AC:L, PR:N, UI:N, C:H, I:H, A:H) suggest a critical vulnerability, likely with a CVSS score of 9.0–10.0 (e.g., remote code execution like Log4Shell). The high impact on confidentiality, integrity, and availability, combined with easy exploitability, makes it a high-priority issue.

Healthcare Context: In a healthcare organization (per prior questions), a network-based vulnerability with high CIA impact could expose PHI, necessitating urgent patching or mitigation to comply with HIPAA.

CS0-003 Relevance: Domain 2 tests interpreting CVSS metrics to prioritize vulnerabilities, often through performance-based questions (PBQs), while Domain 1 emphasizes securing network-exposed systems.

Reference:

CompTIA CySA+ (CS0-003) Exam Objectives, Domains 1 (Security Operations) and 2 (Vulnerability Management),
www.comptia.org, covering CVSS metric analysis.
CompTIA CySA+ Study Guide: Exam CS0-003 by Chapple and Seidl, discussing CVSS 3.0 for vulnerability prioritization.

Explanation:

The question asks for two key factors that a formal change management process should include to reduce the impact of system failures, following a year of critical system failures in an organization. Leveraging an audit tool to identify changes and identifying assets with dependencies that could be impacted are critical to ensuring changes are tracked and potential impacts are assessed, minimizing the risk of failures. These align with the CS0-003 exam’s Security Operations (Domain 1) and Incident Response and Management (Domain 3) objectives, which emphasize proactive management and risk mitigation for critical systems.

Why C and D Are Correct:

C. Leverage an audit tool to identify changes that are being made:
Purpose: Audit tools (e.g., configuration management databases, SIEM systems, or change tracking software like ServiceNow) monitor and log changes to systems, ensuring all modifications (e.g., software updates, configuration changes) are documented and authorized. This helps detect unauthorized or poorly implemented changes that could cause failures.

Reducing Failures: By tracking changes, audit tools enable the organization to identify misconfigurations or untested updates that led to past failures, ensuring proper review and approval before deployment. For example, a tool might flag an unapproved patch that caused a server crash.

Healthcare Context: In a healthcare organization (per prior questions), auditing changes to systems handling PHI ensures compliance with HIPAA and prevents disruptions to critical services (e.g., EHR systems).

CS0-003 Alignment: Domain 1 emphasizes monitoring and auditing system changes to maintain operational integrity, while Domain 3 supports identifying root causes of incidents through change tracking.

D. Identify assets with dependencies that could be impacted by the change:
Purpose: Identifying dependencies (e.g., applications, databases, or services reliant on a system) ensures that changes to one asset don’t cascade to others, causing failures. For example, updating a server might disrupt a dependent application if not planned.

Reducing Failures: Mapping dependencies (e.g., via CMDB or dependency graphs) allows the change management process to assess risks and test impacts before deployment, preventing outages like those experienced previously.

Healthcare Context: In healthcare, dependencies (e.g., a billing system relying on a database) are critical. Identifying these ensures changes don’t disrupt patient care or data access.

CS0-003 Alignment: Domain 1 emphasizes asset management and risk assessment in change processes, while Domain 3 supports preventing incidents by understanding system interdependencies.

Why Other Options Are Incorrect:

A. Ensure users document the system recovery plan prior to deployment
Reason: Documenting a system recovery plan is important for disaster recovery but is not a core component of change management. Change management focuses on controlling and assessing changes to prevent failures, not on post-failure recovery plans. Additionally, “users” documenting recovery plans is impractical, as this is typically an IT or security team responsibility. (Note: This option is listed twice, likely a question error.)

B. Ensure users document the system recovery plan prior to deployment
Reason: Identical to option A, this is likely a duplicate error. It remains incorrect for the same reasons: recovery plans are separate from change management, and users are not typically responsible for documentation.

E. Require diagrams to be completed for all critical systems
Reason: While system diagrams (e.g., network or application architecture) are useful for understanding infrastructure, they are not a direct component of change management. They may support dependency identification (D), but requiring diagrams for all systems is less critical than auditing changes or assessing dependencies to prevent failures.

F. Ensure that all assets are properly listed in the inventory management system
Reason: Maintaining an accurate asset inventory is a foundational practice but is not specific to the change management process. While it supports change management (e.g., knowing which systems to assess), it’s less directly tied to reducing failures compared to auditing changes (C) or identifying dependencies (D), which actively address change-related risks.

Additional Context:

Change Management Process: Based on frameworks like ITIL, change management includes.

Change Request: Submitting and reviewing proposed changes.

Risk Assessment: Identifying impacts and dependencies (D).

Approval: Authorizing changes via a Change Advisory Board (CAB).

Monitoring: Using audit tools to track changes (C).

Testing: Validating changes in a staging environment.

Example:

Audit Tool (C):A SIEM (e.g., Splunk) logs a server patch, revealing it was applied without testing, causing a failure.

Dependencies (D): A CMDB identifies a database dependency, preventing a server update from disrupting a critical application.

CS0-003 Relevance: Domain 1 tests change management to ensure operational stability, while Domain 3 emphasizes preventing incidents through risk assessment and monitoring.

Reference:
CompTIA CySA+ (CS0-003) Exam Objectives, Domains 1 (Security Operations) and 3 (Incident Response and Management), covering change management and risk mitigation.

Explanation:

When a security analyst receives an incident ticket, especially for something time-sensitive like a ransomware attack, they need clear, actionable steps to triage and respond quickly. This is exactly what a playbook provides.

A playbook is a predefined, structured set of actions tailored for specific types of incidents. It includes steps like:

Initial triage

Containment procedures

Indicators of compromise (IOCs) to look for Es

calation paths

Communication guidelines

For ransomware, the playbook may guide the analyst on how to:

Identify infected hosts

Isolate affected systems

Check for backup status

Notify appropriate internal teams

This allows for quick, consistent, and accurate triage and response.

Why the other options are incorrect:

Incident response plan:
This is a high-level document that defines the overall strategy and phases of handling incidents (e.g., preparation, detection, containment). It is not specific enough for hands-on triage of a ransomware ticket.

Lessons learned:
These are documented after an incident is resolved to improve future responses. They are not used for triage during an active event.

Tabletop exercise:
A simulation or discussion-based drill used to test the incident response plan and team readiness. It is a training tool, not an operational aid for triage.

Reference:
CompTIA CySA+ CS0-003 Official Study Guide, section on Incident Response Playbooks It clearly defines a playbook as a step-by-step guide to quickly and consistently handle specific incident types, such as ransomware.

Explanation:

When a security analyst encounters systems that cannot be upgraded or patched due to restrictions imposed by a third-party vendor, this situation reflects a specific type of remediation inhibitor. According to CompTIA CySA+ CS0-003 exam guidance, understanding these inhibitors is essential for risk communication and mitigation planning.

Correct Answer:

Proprietary systems:
Proprietary systems are vendor-controlled technologies that often restrict direct administrative access, including patching or configuration changes. In this scenario:

The company does not have access to the appliance’s operating system.

The appliance is managed under a vendor agreement, meaning updates or changes must be performed by the vendor.

This limits the organization’s ability to remediate vulnerabilities independently.

CompTIA identifies proprietary systems as a common inhibitor to timely remediation, especially when vendors delay updates or lack transparency. These systems require vendor coordination, and sometimes compensating controls, to manage risk effectively.

Incorrect Answer:

Legacy systems:
Legacy systems refer to outdated technologies that may no longer be supported or compatible with modern security tools. While they can be difficult to patch, the scenario does not mention age or obsolescence—only vendor control.

Unsupported operating systems:
Unsupported operating systems are those that no longer receive updates from the manufacturer. The scenario does not indicate that the systems are out of support—just that the company cannot access them due to vendor restrictions.

Lack of maintenance windows :
This refers to scheduling limitations that prevent timely updates. In this case, most systems can be rebooted and patched during a downtime window, so maintenance scheduling is not the issue.

Reference:

CompTIA CySA+ CS0-003 Official Study Guide
CompTIA CySA+ CS0-003 Exam Objectives – Domain 2.2: Implement vulnerability management activities

Explanation:

The Diamond Model of Intrusion Analysis is a structured method for understanding and analyzing cybersecurity intrusions. According to the CompTIA CySA+ CS0-003 Official Study Guide, one of its key benefits is the ability to perform analytical pivoting—moving from one element of an intrusion (e.g., adversary, infrastructure, capability, or victim) to discover related elements.

For example, if you know the infrastructure used in an attack (e.g., an IP address or domain), you can pivot to find:

Other victims targeted by that infrastructure

The adversary’s tools or methods

Related incidents

This pivoting helps analysts:

Map out intrusion campaigns

Fill in knowledge gaps

Improve situational awareness during incident response

Why the other options are incorrect:

"It guarantees that the discovered vulnerability will not be exploited again in the future."
→ No framework or model can guarantee prevention. The Diamond Model is about analysis, not prevention or patching.

"It provides concise evidence that can be used in court."
→ This is more relevant to legal documentation and chain of custody, not the Diamond Model.

"It allows for proactive detection and analysis of attack events."
→ That describes models like MITRE ATT&CK or behavior-based detection. The Diamond Model is primarily post-incident analytical, not proactive.

Reference:
CompTIA CySA+ CS0-003 Official Study Guide, section: Threat Intelligence and Frameworks It describes the Diamond Model as a tool to correlate intrusion events and enable pivoting across different nodes to uncover related elements and intelligence gaps.

Explanation:

The question asks which technology was deployed by a team of analysts developing a new internal system that correlates information from various sources, analyzes it, and triggers notifications based on company policy. SOAR (Security Orchestration, Automation, and Response) is the most fitting technology, as it is designed to integrate data from multiple sources, analyze it, and automate notifications or responses according to predefined policies or playbooks. This aligns with the CS0-003 exam’s Security Operations (Domain 1) and Incident Response and Management (Domain 3) objectives, which emphasize automation, data correlation, and policy-driven responses in a SOC environment.

Why B is Correct:

SOAR Capabilities:

Correlates Information: SOAR platforms (e.g., Splunk SOAR, Palo Alto Cortex XSOAR) integrate data from various sources (e.g., SIEM, EDR, threat intelligence feeds, logs) to create a unified view of security events.

Analyzes Information: SOAR uses analytics and playbooks to process correlated data, identifying threats or incidents (e.g., correlating phishing alerts with endpoint activity).

Triggers Notifications: SOAR automates responses based on company policy, such as sending alerts to analysts, creating tickets, or escalating incidents via email/SMS, using predefined workflows or scripts.

Internal System Development: The system’s focus on correlation, analysis, and policy-driven notifications aligns with SOAR’s orchestration and automation capabilities, which streamline SOC workflows and reduce manual effort.

Healthcare Context: In a healthcare organization (per prior questions), SOAR ensures rapid correlation of threats (e.g., ransomware indicators) and automated notifications to protect PHI, aligning with HIPAA compliance.

CS0-003 Alignment: Domain 1 emphasizes automating security operations through integrated tools, while Domain 3 focuses on orchestrating incident responses, both core strengths of SOAR.

Why Other Options Are Incorrect:

A. SIEM (Security Information and Event Management)
Reason: SIEM systems (e.g., Splunk, QRadar) collect and correlate logs from various sources, analyze them for anomalies, and generate alerts. While SIEM performs correlation and analysis, it primarily focuses on monitoring and alerting, not automating complex workflows or triggering policy-based notifications like SOAR. SIEM is often a data source for SOAR, not the complete solution described.

C. IPS (Intrusion Prevention System)
Reason: An IPS detects and blocks malicious network traffic based on signatures or anomalies (e.g., blocking SQL injection attempts). It doesn’t correlate data from multiple sources or trigger policy-based notifications beyond basic alerts. IPS is a preventive control, not a system for analysis and automation like SOAR.

D. CERT (Computer Emergency Response Team)
Reason: CERT is not a technology but a team or organization responsible for coordinating incident response and sharing threat intelligence. It doesn’t correlate data or automate notifications, making it irrelevant to the system described.

Additional Context:

SOAR in Action:

Correlation: Integrates SIEM logs, EDR alerts (e.g., CrowdStrike), and threat feeds (e.g., STIX/TAXII) to identify incidents like phishing campaigns.

Analysis: Uses playbooks to analyze events (e.g., checking if a suspicious IP matches known malware C2 servers).

Notifications: Automates actions per company policy (e.g., notifying the SOC via Slack for high-severity incidents or escalating to the CISO for PHI breaches).

Example: A SOAR system might correlate a phishing email with endpoint malware detection, analyze the threat, and trigger a notification to quarantine the affected system, all based on predefined rules.

CS0-003 Relevance: Domain 1 tests selecting tools for SOC automation, while Domain 3 emphasizes automating incident response workflows, both favoring SOAR.

Reference:
CompTIA CySA+ (CS0-003) Exam Objectives, Domains 1 (Security Operations) and 3 (Incident Response and Management), covering automation and orchestration tools.

Explanation:

The question asks for the best method to mitigate a buffer overflow vulnerability in a critical application at the application level, identified during a security test. Implementing input validation is the most effective application-level mitigation, as it directly addresses the root cause of buffer overflows by ensuring that user inputs are properly checked and sanitized, preventing excessive or malicious data from overflowing memory buffers. This aligns with the CS0-003 exam’s Vulnerability Management (Domain 2) and Security Operations (Domain 1) objectives, which emphasize securing applications and mitigating vulnerabilities at the source. CompTIA CySA+ Study Guide: Exam CS0-003 by Chapple and Seidl, discussing SOAR for data correlation and automated response.

Why B is Correct:

Buffer Overflow Vulnerability:
A buffer overflow occurs when an application writes more data to a memory buffer than it can hold, potentially allowing malicious code execution or system crashes. This is often caused by improper handling of user inputs (e.g., overly long strings in a form field).

Input Validation:
Implementing input validation ensures that user inputs are checked for length, format, and content before processing (e.g., rejecting inputs exceeding buffer size or containing malicious payloads). This prevents the conditions that trigger buffer overflows, addressing the vulnerability at the application code level.

Application-Level Focus:
The question specifies mitigation at the application level, meaning changes to the application’s code or logic (e.g., adding checks in C, Java, or Python code), not system-level or external measures.

Healthcare Context:
In a healthcare organization (per prior questions), a critical application (e.g., EHR system) with a buffer overflow could expose PHI or disrupt services. Input validation ensures robust application security, aligning with HIPAA requirements.

CS0-003 Alignment:
Domain 2 emphasizes mitigating application vulnerabilities through secure coding practices, while Domain 1 supports implementing application-level controls to protect critical systems.

Why Other Options Are Incorrect:

A. Perform OS hardening
Reason: OS hardening (e.g., disabling unnecessary services, applying patches) strengthens the operating system but is not an application-level mitigation. It doesn’t directly address the application’s buffer overflow, which stems from coding flaws. Hardening may reduce exploit impact but isn’t the best fix for the vulnerability itself.

C. Update third-party dependencies
Reason: Updating third-party dependencies (e.g., libraries like OpenSSL) mitigates vulnerabilities in external code but doesn’t directly address a buffer overflow in the application’s own code. Unless the vulnerability is explicitly in a library, input validation is more targeted for application-level fixes.

D. Configure address space layout randomization (ASLR)
Reason: ASLR randomizes memory addresses to make buffer overflow exploits harder, but it’s a system-level mitigation (configured at the OS or compiler level), not an application-level fix. It reduces exploit success but doesn’t prevent the overflow, unlike input validation, which fixes the root cause in the application code.

Additional Context:

Input Validation Examples:

In C: Check input length with strncmp or use safe functions like fgets instead of gets.
In Java: Use String.length() to enforce input limits.
In web apps: Validate form inputs (e.g., max length of 100 characters) before processing.
Buffer Overflow Mitigation: Beyond input validation, other application-level practices include using safe libraries (e.g., strncpy vs. strcpy) and bounds checking, but validation is the primary defense against malicious inputs.
CS0-003 Relevance: Domain 2 tests secure coding practices to mitigate vulnerabilities, often through performance-based questions (PBQs), while Domain 1 emphasizes protecting critical applications.

Reference:

CompTIA CySA+ (CS0-003) Exam Objectives, Domains 1 (Security Operations) and 2 (Vulnerability Management),
www.comptia.org, covering application security and vulnerability mitigation.
CompTIA CySA+ Study Guide: Exam CS0-003 by Chapple and Seidl, discussing secure coding for buffer overflow prevention.