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

D ("grnail.com") is a suspicious domain that resembles "gmail.com."

The high "bytes out" value (525,984 bytes) indicates potential data exfiltration.

Attackers often use typosquatting (e.g., "grnail.com" instead of "gmail.com") to trick users into visiting malicious sites.

Why Not Other Options?

A (Netflix, B YouTube, C TikTok) → Large downloads, but expected behavior for streaming sites.

E (Google Translate) → Low data volume, no exfiltration risk.

F (Office.com) → Microsoft service, no indication of malicious activity.

A web application firewall (WAF) is a tool that can protect web servers from attacks such as SQL injection, cross-site scripting, and other web-based threats. A WAF can filter, monitor, and block malicious HTTP traffic before it reaches the web server. A WAF can also be configured with rules and policies to detect and prevent specific types of attacks.

1. How many employees clicked on the link in the phishing email?

According to the email server logs, 25 employees clicked on the link in the phishing email.

2. On how many workstations was the malware installed?

According to the file server logs, the malware was installed on 15 workstations.

3. What is the executable file name of the malware?

The executable file name of the malware is svchost.EXE.

Answers

1. 25

2. 15

3. svchost.EXE

TheDiamond Model of Intrusion Analysisconsists offour core attributes:

Adversary– The threat actor behind the attack.

Capability– The tools and techniques used.

Infrastructure– The systems used by the adversary (e.g., botnets, C2 servers).

Victim– The target of the attack​.

Option A (Delivery)andOption B (Weaponization)are part of theCyber Kill Chain, not the Diamond Model.

Option C (Command and control)is an attack phase butnot a core attribute of the Diamond Model.

Option D (Capability) is correct, as it represents the tools and attack methods used by adversaries.

Thus,D is the correct answer.

After recovering a compromised server to its previous state, the analyst should perform forensic analysis to determine the root cause, impact, and scope of the incident, as well as to identify any indicators of compromise, evidence, or artifacts that can be used for further investigation or prosecution. References: CompTIA CySA+ Study Guide: Exam CS0-003, 3rd Edition, Chapter 6, page 244; CompTIA CySA+ CS0-003 Certification Study Guide, Chapter 6, page 253.

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.

Registry key values would be missing from a scan performed with this configuration, as the scanner appliance would not have access to the Windows Registry of the scanned systems. The WindowsRegistry is a database that stores configuration settings and options for the operating system and installed applications. To scan the Registry, the scanner would need to have credentials to log in to the systems and run a local agent or script. The other items would not be missing from the scan, as they can be detected by the scanner appliance without credentials. Operating system version can be identified by analyzing service banners or fingerprinting techniques. Open ports can be discovered by performing a port scan or sending probes to common ports. IP address can be obtained by resolving the hostname or using network discovery tools. https://attack.mitre.org/techniques/T1112/

The Diamond Model of Intrusion Analysis is a framework that describes the relationship between four components of a cyberattack: adversary, capability, infrastructure, and victim. It helps analysts understand the behavior and motivation of threat actors, as well as the tools and methods they use to compromise their targets12. References: Main Analytical Frameworks for Cyber Threat Intelligence, section 4; Strategies, tools, and frameworks for building an effective threat intelligence team, section 3.

Tocapture and analyze network traffic, the two best tools are:

tcpdump (Option A)– A command-line packet capture tool used for network traffic analysis.

Wireshark (Option D)– A GUI-based network packet analysis tool that provides deep inspection capabilities​.

Option B (SIEM)is forlog aggregationand does notcapturetraffic.

Option C (Vulnerability scanner)identifies weaknesses but does notcapturenetwork traffic.

Option E (Nmap)is used for network discovery and port scanning, not capturing traffic.

Option F (SOAR)automates security processes but does not capture traffic.

Thus,A (tcpdump) and D (Wireshark) are correct, asthey are the best tools for capturing and analyzing anomalous network traffic​.

Passive network foot printing is the best description of the example, as it reflects the technique of collecting information about a network or system by monitoring or sniffing network traffic without sending any packets or interacting with the target. Foot printing is a term that refers to the process of gathering information about a target network or system, such as its IP addresses, open ports, operating systems, services, or vulnerabilities. Foot printing can be done for legitimate purposes, such as penetration testing or auditing, or for malicious purposes, such as reconnaissance or intelligence gathering. Foot printing can be classified into two types: active and passive. Active foot printing involves sending packets or requests to the target and analyzing the responses, such as using tools like ping, traceroute, or Nmap. Active foot printing can provide more accurate and detailed information, but it can also be detected by firewalls or intrusion detection systems (IDS). Passive foot printing involves observing or capturing network traffic without sending any packets or requests to the target, such as using tools like tcpdump, Wireshark, or Shodan. Passive foot printing can provide less information, but it can also avoid detection by firewalls or IDS. The example in the question shows that the attacker has gained access to the syslog server on a LAN and reviewed the syslog entries to prioritize possible next targets. A syslog server is a server that collects and stores log messages from various devices or applications on a network. A syslog entry is a record of an event or activity that occurred on a device or application, such as an error, a warning, or an alert. By reviewing the syslog entries, the attacker can obtain information about the network or system, such as its configuration, status, performance, or security issues. This is an example of passive network foot printing, as the attacker is not sending any packets or requests to the target, but rather observing or capturing network traffic from the syslog server. The other options are not correct, as they describe different techniques or concepts. OS fingerprinting is a technique of identifying the operating system of a target by analyzing its responses to certain packets or requests, such as using tools like Nmap or Xprobe2. OS fingerprinting can be done actively or passively, but it is not what the attacker is doing in the example. Service port identification is a technique of identifying the services running on a target by scanning its open ports and analyzing its responses to certain packets or requests, such as using tools like Nmap or Netcat. Service port identification can be done actively or passively, but it is not what the attacker is doing in the example. Application versioning is a concept that refers to the process of assigning unique identifiers to different versions of an application, such as using numbers, letters, dates, or names. Application versioning canhelp to track changes, updates, bugs, or features of an application, but it is not related to what the attacker is doing in the example.

Port 3389 is commonly used by Remote Desktop Protocol (RDP), which is a service that allows remote access to a system. A vulnerability on this port could allow an attacker to compromise the web server or use it as a pivot point to access other systems. However, if the firewall blocks this port, the risk of exploitation is reduced.

The XML file containsJavaScript embedded within a tagthat executes an alert message, which is a commonCross-Site Scripting (XSS)attack vector. The issue occurs becausethe XML schema does not restrict the input to safe characters, allowingarbitrary script executionwhen the XML file is processed by a vulnerable application.

Solution: Implement Input Validation Using an XML Schema Constraint

Option Benforces awhitelist approachby allowingonly alphanumeric characters and spaces([a-zA-Z 0-9]*).

This prevents the inclusion ofmalicious JavaScript or special characterssuch as <, >, or &, which are required for XSS injection​.

Why are the other options incorrect?

Option A: Restricts input to aSocial Security Number (SSN) format ([0-9]{3}-[0-9]{2}-[0-9]{4}). While it prevents JavaScript injection, it is too restrictive and would break legitimate text-based content in the XML.

Option C: Restricts input toonly numeric values ([0-9]*), preventing JavaScript injection but also breaking legitimate non-numeric content in the field.

Option D: Restricts input to asingle positive integer, which does not align with the expected text-based content.

Thus,Option Bis the correct answer, as it enforces proper input validation while still allowing expected text input​.

A security analyst’s concern is that any discovered vulnerabilities in the OS that is approaching the end-of-life date will not be remediated by the vendor, leaving the system exposed to potential attacks. The other options are not directly related to the security analyst’s role or responsibility. Verified References: CompTIA Cybersecurity Analyst (CySA+) Certification Exam Objectives, page 9, section 2.21

To determine the correct priority, you must filter the options by applying the rules from Security Policy 1006 in the order of importance dictated by the scenario.

“The Company shall prioritize patching of publicly available systems and services over patching of internally available system.”

Option A: Internal System

Option B: External System (Keep)

Option C: External System (Keep)

Option D: Internal System

Result: Eliminate Options A and D. We are now choosing between B and C.

“In situations where a choice must be made between confidentiality and availability, the Company shall prioritize confidentiality of data over availability of systems and data.”

To apply this, you must read the CVSS v3.1 Vector String for the remaining options. The relevant metrics are C (Confidentiality) and A (Availability).

Option B (CAP.SHIELD): C:H / I:N / A:N

Confidentiality: High (C:H)

Availability: None (A:N)

Interpretation: This vulnerability allows for a significant breach of data confidentiality.

Option C (LOKI.DAGGER): C:N / I:N / A:H

Confidentiality: None (C:N)

Availability: High (A:H)

Interpretation: This vulnerability allows for a significant disruption of service (DoS).

Conclusion: Since the policy explicitly prioritizes Confidentiality (Option B) over Availability (Option C), Option B is the highest priority.

The exam expects you to parse raw CVSS strings to assess risk. Here is the breakdown for the correct answer (Option B):

Metric

Code

Value

Meaning

AV

AV:N

Network

The vulnerability is exploitable remotely via the network (most dangerous).

AC

AC:L

Low

No complex conditions are required to exploit.

PR

PR:N

None

No privileges are required (unauthenticated).

UI

UI:N

None

No user interaction is required.

C

C:H

High

Confidentiality Impact. Total loss of confidentiality.

A

A:N

None

Availability Impact. No impact to uptime.

APIs (Application Programming Interfaces) enable integration and automation across different vendor platforms within a SOAR (Security Orchestration, Automation, and Response) solution. They allow security tools to communicate and execute automated actions, making them essential for orchestrating responses across diverse systems and platforms. While STIX/TAXII provides standards for threat information sharing, and data enrichment enhances context, APIs are the primary means of enabling cross-platform automation, as recommended in CompTIA CySA+ materials on SOAR operations.

Group Policy Objects (GPO) are a feature in Windows environments that allow administrators to control settings and permissions across user accounts and computers within an organization. GPOs can restrict user permissions to prevent unauthorized installation or modification of applications, making them the best choice for centrally managing user capabilities on Windows systems. While HIPS (Host Intrusion Prevention Systems), Registry, and DLP (Data Loss Prevention) have their own uses, GPOs provide a scalable and enterprise-level solution for application control as per CompTIA Security+ guidelines.

Sandboxing is a technique that isolates potentially malicious programs or files in a controlled environment, preventing them from affecting the rest of the system. It can help mitigate the effects of a new ransomware attack by preventing it from encrypting or deleting important data or spreading to other devices. References: CompTIA CySA+ Study Guide: Exam CS0-003, 3rd Edition, Chapter 5, page 202; CompTIA CySA+ CS0-003 Certification Study Guide, Chapter 5, page 210.

The correct answer is A. Address space layout randomization.

Address space layout randomization (ASLR) is a security control that randomizes the memory address space of a process, making it harder for an attacker to exploit memory-based vulnerabilities, such as buffer overflows1. ASLR can also prevent a security analyst from finding the proper memory address of a piece of malicious code, as the memory address changes every time the process runs2.

The other options are not the best explanations for why the memory address changes every time the process runs. Data execution prevention (B) is a security control that prevents code from being executed in certain memory regions, such as the stack or the heap3. Stack canary © is a security technique that places a random value on the stack before a function’s return address, to detect and prevent stack buffer overflows. Code obfuscation (D) is a technique that modifies the source code or binary of a program to make it more difficult to understand or reverse engineer. These techniques do not affect the memory address space of a process, but rather the execution or analysis of the code.