CompTIA  CS0-003  CySA+  Exam Dumps and Practice Test Questions Set 1 Q1-20

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Question 1
Which of the following is the most effective method to detect a zero-day exploit targeting a known vulnerable application on a network?

A) Signature-based antivirus scans
B) Behavioral-based intrusion detection system
C) Regular vulnerability scanning
D) Patch management

Answer B

Explanation:

A Signature-based antivirus scans
Signature-based antivirus relies on known patterns or signatures of malware. While this is effective against known threats, zero-day exploits are unknown vulnerabilities that have not yet been documented. A signature-based system cannot detect new, unknown threats because it has no prior record of the exploit, making it ineffective for zero-day detection.

B Behavioral-based intrusion detection system
Behavioral-based intrusion detection systems (IDS) analyze patterns of activity and flag anomalies that deviate from normal system behavior. This approach is effective for detecting zero-day exploits because it does not rely on known signatures. Instead, it identifies suspicious activity, such as unusual process behavior, abnormal network traffic, or privilege escalation attempts. By focusing on the behavior of applications and users rather than known malware patterns, it increases the likelihood of detecting previously unknown threats, making it the most suitable method among the given options.

C Regular vulnerability scanning
Vulnerability scanning is designed to identify known weaknesses in systems and applications. It relies on a database of known vulnerabilities and cannot detect attacks exploiting unknown flaws. While vulnerability scanning is essential for proactive security posture, it is not a primary tool for detecting zero-day exploits in real-time.

D Patch management
Patch management helps reduce the attack surface by updating software to fix known vulnerabilities. Although it reduces the likelihood of successful attacks, it cannot detect zero-day exploits that occur before a patch is released. Therefore, while necessary, it is not an effective detection method.

Question 2
During a network investigation, a security analyst notices repeated login attempts from multiple IP addresses in a short time frame targeting an admin account. Which of the following attacks is most likely occurring?

A) Brute force attack
B) Phishing attack
C) SQL injection
D) Man-in-the-middle attack

Answer A

Explanation:

A Brute force attack
A brute force attack attempts to gain access to accounts by systematically trying all possible password combinations. Repeated login attempts from multiple IP addresses, often referred to as a distributed brute force attack, indicate automated tools are being used to crack credentials. The pattern of repeated, rapid attempts is characteristic of brute force attacks and aligns with the scenario described.

B Phishing attack
Phishing attacks attempt to trick users into disclosing credentials through deceptive emails, websites, or messages. Phishing does not generate repeated login attempts directly on a target system, so this scenario does not indicate phishing as the primary attack.

C SQL injection
SQL injection targets database queries by inserting malicious SQL statements. While it can allow attackers to bypass authentication, it does not typically involve repeated login attempts from multiple IP addresses, so it is not the most likely attack here.

D Man-in-the-middle attack
Man-in-the-middle attacks intercept communication between two parties to eavesdrop or manipulate data. This attack does not inherently involve repeated login attempts on a specific account and is therefore not consistent with the described pattern.

Question 3
Which of the following is a key advantage of implementing a Security Information and Event Management (SIEM) system in an enterprise environment?

A) Automates patch deployment
B) Centralizes log collection and correlation
C) Replaces endpoint antivirus software
D) Encrypts network traffic

Answer B

Explanation:

A Automates patch deployment
SIEM systems do not manage patching. Patch deployment is handled by endpoint management or configuration management tools. While SIEM can alert administrators to vulnerable systems, it does not directly automate patching.

B Centralizes log collection and correlation
SIEM solutions collect logs from multiple sources, including servers, firewalls, endpoints, and applications. They correlate this data to identify suspicious patterns, trends, or incidents. Centralized log collection enables faster detection of threats, improved incident response, and comprehensive reporting. By aggregating and analyzing large volumes of data, SIEM helps security teams identify and respond to attacks that may not be obvious from individual logs, making this its key advantage.

C Replaces endpoint antivirus software
SIEM does not provide endpoint-level protection. While it enhances detection and monitoring capabilities, it does not replace antivirus or endpoint detection and response tools.

D Encrypts network traffic
SIEM systems focus on monitoring, detection, and alerting rather than encrypting traffic. Encryption is handled by protocols like TLS or VPN solutions, not by SIEM.

Question 4
A security analyst is investigating unusual outbound traffic from a server. The traffic is encrypted and directed to an unfamiliar IP address on port 443. Which of the following is the most likely concern?

A) Ransomware communicating with a C2 server
B) SQL injection attack
C) Unauthorized patch update
D) Phishing email being sent

Answer A

Explanation:

A Ransomware communicating with a C2 server
Ransomware and other malware often communicate with command-and-control (C2) servers to receive instructions, exfiltrate data, or report infection status. Encrypted outbound traffic to an unfamiliar IP on standard HTTPS port 443 is a common indicator of C2 activity. Since the traffic is unusual and unexpected, it raises concern for a potential malware infection, such as ransomware.

B SQL injection attack
SQL injection is an attack against a database via malicious input. It does not inherently involve encrypted outbound communication to external IPs, making this option less likely.

C Unauthorized patch update
Patch updates typically come from trusted sources and do not involve traffic to unfamiliar external IP addresses. Unexpected traffic to unknown hosts is therefore suspicious and not likely legitimate patch activity.

D Phishing email being sent
Phishing emails are generally sent via mail servers or compromised accounts. Encrypted traffic to a single external IP on port 443 does not match the usual patterns of mass email sending, so this is not the primary concern.

Question 5
Which of the following best describes the purpose of a threat hunting program within a SOC?

A) To reactively respond to alerts generated by automated tools
B) To proactively search for undetected threats and anomalies
C) To configure firewalls and access controls
D) To patch vulnerable systems across the network

Answer B

Explanation:

A To reactively respond to alerts generated by automated tools
Reactive response involves responding to alerts from SIEM, IDS, or other automated tools. While important, threat hunting is proactive and does not rely solely on alerts—it seeks out hidden threats before they trigger alarms.

B To proactively search for undetected threats and anomalies
Threat hunting involves security analysts actively looking for threats that bypass automated detection systems. By analyzing network traffic, logs, and system behavior, analysts can uncover malware, insider threats, or attack techniques that are not immediately visible. This proactive approach improves the organization’s security posture and allows mitigation before significant damage occurs. Threat hunting complements, rather than replaces, automated tools by focusing on subtle indicators of compromise and advanced persistent threats.

C To configure firewalls and access controls
Configuring firewalls and access controls is a preventative measure and part of standard network administration. It is not the primary purpose of a threat hunting program, which focuses on detection rather than configuration.

D To patch vulnerable systems across the network
Patching reduces vulnerability exposure, but it is a preventative control. Threat hunting, in contrast, involves identifying and responding to threats already present in the environment.

Question 6
A security analyst notices that multiple endpoints are suddenly sending large amounts of outbound traffic to an external IP address. Which of the following is the most likely cause?

A) Distributed Denial of Service (DDoS) attack
B) Data exfiltration
C) Port scanning
D) Brute force attack

Answer B

Explanation:

A Distributed Denial of Service (DDoS) attack
A DDoS attack typically involves overwhelming a target system with traffic from multiple sources, causing disruption. While multiple endpoints generating traffic may resemble DDoS activity, the described scenario involves outbound traffic from internal hosts rather than traffic targeting a victim. DDoS is usually inbound-focused, so it is less likely in this case.

B Data exfiltration
Data exfiltration occurs when sensitive or proprietary information is transferred from internal systems to external entities without authorization. The scenario describes multiple endpoints sending large amounts of outbound data to an external IP, which is consistent with exfiltration activity. This behavior is a common indicator of compromise, suggesting that malware or an insider may be transferring data to an attacker-controlled server.

C Port scanning
Port scanning is a reconnaissance activity that targets various ports on external systems to identify vulnerabilities. It usually generates inbound traffic patterns when detected by IDS, but it does not involve large-scale outbound data transfers from multiple internal systems. Therefore, this option does not align with the scenario.

D Brute force attack
Brute force attacks attempt to gain access by systematically trying passwords or credentials. This activity does not produce large volumes of outbound traffic from multiple endpoints to a single external IP, so it is not consistent with the scenario.

Question 7
Which of the following is the primary purpose of implementing network segmentation in an enterprise environment?

A) Increase bandwidth for internal traffic
B) Reduce the attack surface and limit lateral movement
C) Simplify patch management
D) Replace endpoint antivirus controls

Answer B

Explanation:

A Increase bandwidth for internal traffic
While segmenting networks can sometimes optimize traffic flows, the main goal of network segmentation is not to increase bandwidth. Bandwidth may incidentally improve in some cases, but it is not the primary purpose from a cybersecurity perspective.

B Reduce the attack surface and limit lateral movement
Network segmentation divides the network into smaller, isolated zones. By restricting communication between segments, it prevents attackers from moving freely across the network if a system is compromised. Segmentation helps contain breaches, enforce security policies, and improve monitoring. This control is crucial for protecting sensitive systems and limiting the impact of malware or insider threats.

C Simplify patch management
Network segmentation does not directly simplify patching. Patch management is handled by dedicated tools and processes. Segmentation may indirectly support security by isolating vulnerable systems, but simplifying patching is not its primary purpose.

D Replace endpoint antivirus controls
Segmentation is not a substitute for endpoint protection. Endpoint antivirus remains essential to detect and mitigate malware on individual devices. Segmentation complements security controls but does not replace them.

Question 8
During a log review, a security analyst observes repeated failed login attempts followed by a successful login using an admin account outside business hours. Which of the following actions should the analyst perform first?

A) Notify human resources
B) Isolate the affected account and reset the password
C) Reboot the server to terminate sessions
D) Perform a vulnerability scan

Answer B

Explanation:

A Notify human resources
While notifying HR may be necessary if insider threat is suspected, it is not the immediate first step. The primary concern is securing the potentially compromised account before further damage occurs.

B Isolate the affected account and reset the password
The first action in response to a suspected compromised account is to contain the threat. Isolating the account and resetting the password prevents the attacker from continuing to access critical systems. This immediate containment step mitigates risk, allowing analysts to investigate further without additional exposure.

C Reboot the server to terminate sessions
Rebooting the server may terminate active sessions but does not secure the compromised credentials. Attackers could still regain access with valid credentials, so this action is not sufficient or prioritized over account isolation.

D Perform a vulnerability scan
Scanning for vulnerabilities is a proactive security measure but does not address the immediate threat. The compromised account must be contained first, and scanning can be performed as part of a follow-up investigation.

Question 9
A security analyst receives an alert that an employee’s endpoint is communicating with a known malicious IP. The endpoint appears to be running normal processes. Which type of analysis should the analyst perform next?

A) Static malware analysis
B) Dynamic malware analysis
C) Log correlation and network traffic analysis
D) Social engineering assessment

Answer C

Explanation:

A Static malware analysis
Static analysis examines a malware sample’s code without executing it. In this case, there is no sample identified yet; the concern is network communication from an endpoint. Static analysis would not provide immediate insights into live network behavior.

B Dynamic malware analysis
Dynamic analysis involves executing malware in a controlled environment to observe behavior. While useful for reverse engineering, the immediate need is to determine why the endpoint is communicating with a malicious IP. Dynamic analysis is not the first step.

C Log correlation and network traffic analysis
Network traffic and log correlation allow the analyst to understand the scope and nature of the communication. By analyzing endpoint logs, firewall logs, and IDS alerts, the analyst can identify what processes or users are involved, which systems may be affected, and whether the connection is part of a larger attack. This step helps determine whether further containment, threat hunting, or malware analysis is required.

D Social engineering assessment
Social engineering assessment evaluates human factors or phishing susceptibility. While important in security programs, it is not relevant to analyzing an endpoint communicating with a malicious IP in this scenario.

Question 10
Which of the following security controls is best for detecting abnormal behavior in network traffic that could indicate a data exfiltration attempt?

A) Network-based intrusion detection system (NIDS)
B) Firewall rule for blocking incoming traffic
C) Regular vulnerability scanning
D) Patch management automation

Answer A

Explanation:

A Network-based intrusion detection system (NIDS)
A NIDS monitors network traffic in real time and compares it against known attack signatures and behavioral patterns. By analyzing packet flows, connections, and protocols, it can detect anomalies such as large outbound data transfers, unusual ports, or unexpected destinations. NIDS is especially effective for detecting exfiltration attempts because it can identify suspicious behavior even if the data is encrypted, alerting analysts before significant loss occurs.

B Firewall rule for blocking incoming traffic
Firewalls primarily enforce access policies by allowing or denying traffic. While they can block unauthorized inbound connections, they are not optimized for detecting subtle, anomalous outbound behavior indicative of exfiltration.

C Regular vulnerability scanning
Vulnerability scanning identifies known security weaknesses but does not detect real-time anomalies in network traffic. It is a preventative measure rather than a monitoring tool.

D Patch management automation
Patch management ensures systems are updated and reduces vulnerabilities but does not detect or alert on abnormal traffic. It is a preventative control, not a detection mechanism.

Question 11
An organization implements a new endpoint detection and response (EDR) tool. After deployment, a security analyst observes unusual process behavior on several workstations. Which of the following is the most appropriate next step?

A) Disable the EDR agent on affected endpoints
B) Investigate the processes using threat intelligence and logs
C) Reimage all affected workstations immediately
D) Notify legal and compliance teams

Answer B

Explanation:

A Disable the EDR agent on affected endpoints
Disabling the EDR agent would remove critical visibility into endpoint activity and hinder the investigation. It is not a recommended action because it may allow malicious activity to continue undetected.

B Investigate the processes using threat intelligence and logs
The primary purpose of EDR tools is to provide visibility into endpoint behavior. Observing unusual processes should prompt an analyst to correlate logs, analyze process attributes, and reference threat intelligence sources to determine whether the behavior is malicious or benign. This step allows a measured, informed response before taking disruptive actions such as reimaging. It ensures containment and proper analysis while preserving forensic evidence.

C Reimage all affected workstations immediately
Reimaging can be a necessary remediation step but doing it immediately without understanding the nature of the processes risks destroying valuable evidence. Analysts should investigate first to confirm the presence of malware or unauthorized activity before taking such drastic measures.

D Notify legal and compliance teams
While notification may be required if sensitive data is at risk, involving legal or compliance should occur after initial investigation confirms a security incident. Immediate notification without analysis may create unnecessary administrative overhead.

 

Question 12
During a threat-hunting exercise, an analyst identifies unusual DNS requests from internal hosts to external domains that are randomly generated. Which type of malware behavior does this most likely indicate?

A) Keylogger activity
B) Domain Generation Algorithm (DGA)
C) Ransomware encryption
D) Phishing email campaign

Answer B

Explanation:

A Keylogger activity
Keyloggers record keystrokes and may exfiltrate data, but they typically do not generate random DNS queries. While a keylogger may communicate with a C2 server, the random DNS requests described are not characteristic of keylogger behavior.

B Domain Generation Algorithm (DGA)
DGAs are used by malware to dynamically generate domain names to communicate with command-and-control servers. The random and frequent DNS queries observed from internal hosts strongly suggest DGA activity. DGAs help malware evade detection by frequently changing domains, making hard-coded blacklists ineffective. Detecting DGA behavior is a key aspect of threat hunting and helps analysts identify infected systems and prevent exfiltration or further compromise.

C Ransomware encryption
Ransomware primarily focuses on encrypting files on the victim system. While it may communicate with C2 servers, random DNS requests are not its defining behavior, so this does not match the described pattern.

D Phishing email campaign
Phishing campaigns generally involve sending deceptive messages to users and do not inherently generate randomized DNS queries from internal systems. Therefore, this is unlikely the cause of the observed behavior.

Question 13
A security analyst receives multiple alerts indicating repeated SQL injection attempts on a web application. Which of the following controls should be implemented to prevent this type of attack?

A) Input validation and parameterized queries
B) Network segmentation
C) EDR deployment
D) Security awareness training

Answer A

Explanation:

A Input validation and parameterized queries
SQL injection occurs when untrusted input is improperly handled by an application and executed as part of a database query. Implementing proper input validation ensures that only expected data types and formats are processed. Parameterized queries or prepared statements separate code from data, preventing malicious input from modifying SQL logic. This approach is the most effective technical control for preventing SQL injection attacks at the application level.

B Network segmentation
While network segmentation limits lateral movement, it does not directly prevent attacks targeting vulnerabilities in web application code. It is a preventative control for containment rather than input validation.

C EDR deployment
Endpoint detection and response tools focus on monitoring and responding to malicious activity on endpoints. They are useful for detecting malware or suspicious behavior but do not prevent web application vulnerabilities like SQL injection.

D Security awareness training
User training can help prevent social engineering attacks but does not directly prevent attackers from exploiting SQL injection vulnerabilities in web applications. It complements technical controls but is not sufficient on its own.

Question 14
During an investigation, an analyst notices that a previously unknown process is creating outbound connections to several external IPs on high-numbered ports. Which of the following steps should the analyst take first?

A) Terminate the process immediately without investigation
B) Capture network traffic and analyze logs
C) Reimage the affected system
D) Notify senior management

Answer B

Explanation:

A Terminate the process immediately without investigation
Terminating the process without investigation may stop the immediate threat but will destroy critical forensic evidence. Analysts need to preserve data to understand the scope, origin, and behavior of the potential malware.

B Capture network traffic and analyze logs
The first step in investigating unusual outbound connections is to capture network traffic and review system and network logs. This allows the analyst to identify the nature of the connection, determine the endpoints involved, assess potential data exfiltration, and confirm whether the activity is malicious. It is a methodical approach that preserves evidence while informing further remediation.

C Reimage the affected system
Reimaging may be necessary if the system is confirmed to be compromised, but it should occur after the investigation to avoid losing evidence needed for analysis or compliance.

D Notify senior management
While important for awareness, management notification is not the first technical step. Initial containment and evidence gathering should occur first to provide accurate information for escalation.

Question 15
Which of the following is the primary goal of implementing honeypots in a cybersecurity environment?

A) Prevent malware from entering the network
B) Collect intelligence on attacker methods and tactics
C) Automatically patch vulnerable systems
D) Encrypt sensitive data at rest

Answer B

Explanation:

A Prevent malware from entering the network
Honeypots are not primarily preventative; they are decoy systems designed to attract attackers. While they may divert attacks away from production systems, their main function is not to block malware entry.

B Collect intelligence on attacker methods and tactics
Honeypots serve as monitoring systems that simulate vulnerable or valuable targets. When attackers interact with honeypots, analysts can observe attack techniques, malware behavior, and tools used. This intelligence improves detection capabilities, informs threat hunting, and supports incident response planning. Honeypots provide actionable insights into attacker behavior without putting critical production systems at risk.

C Automatically patch vulnerable systems
Honeypots do not manage or patch vulnerabilities; they deliberately simulate weaknesses to attract attackers for observation.

D Encrypt sensitive data at rest
Data encryption is unrelated to honeypots. Honeypots focus on deception and intelligence gathering, not data protection through encryption.

Question 16
A security analyst notices an unusual spike in outbound traffic from multiple endpoints to an external server over HTTPS. The traffic appears encrypted and occurs at irregular intervals. Which of the following is the most likely scenario?

A) Distributed Denial of Service (DDoS)
B) Data exfiltration by malware
C) Routine software updates
D) Phishing campaign

Answer B

Explanation:

A Distributed Denial of Service (DDoS)
DDoS attacks aim to overwhelm a target server or network with traffic, causing disruption or downtime. These attacks typically manifest as inbound traffic spikes targeting the victim, not outbound traffic from internal systems. While high outbound traffic could theoretically be part of a botnet participating in a DDoS attack, the description emphasizes encrypted traffic to a single external server at irregular intervals, which does not match typical DDoS patterns. DDoS is generally volumetric and synchronized, whereas the scenario describes stealthy, intermittent activity indicative of exfiltration rather than denial of service.

B Data exfiltration by malware
Data exfiltration involves unauthorized transfer of sensitive or confidential information from internal systems to external locations controlled by an attacker. The scenario fits classic indicators: multiple endpoints involved, irregular encrypted outbound traffic, and communication with an external server. Malware often uses encryption (such as HTTPS or custom protocols) to evade detection by security tools like IDS or firewalls. The irregular timing may reflect automated malware designed to avoid traffic analysis or threshold-based detection. Detecting this requires network monitoring, traffic analysis, and correlation with endpoint logs to confirm which systems are compromised and the type of data being exfiltrated. Effective response involves isolating affected endpoints, analyzing the malware or unauthorized processes, and implementing controls such as data loss prevention (DLP) and enhanced network monitoring.

C Routine software updates
Routine updates, such as OS or application patches, may generate outbound encrypted traffic, typically to known vendor servers. However, these connections are predictable, often scheduled, and usually originate from standard processes like Windows Update, package managers, or IT management tools. The irregularity of traffic and its targeting of an unfamiliar server suggests this is unlikely routine updates. Analysts must always compare against expected traffic baselines to differentiate between legitimate and malicious activity.

D Phishing campaign
Phishing involves tricking users into divulging credentials or executing malicious code. While phishing could indirectly lead to malware and subsequent exfiltration, the traffic itself is a result of malware behavior rather than the phishing emails. Observing outbound encrypted traffic without initial user interaction points toward active data exfiltration rather than the email-based phishing stage.

Question 17
Which of the following techniques is most effective for detecting lateral movement within a segmented corporate network?

A) Network-based intrusion detection system (NIDS) with anomaly detection
B) Firewall rules blocking inbound traffic
C) Antivirus signature updates
D) Phishing simulations

Answer A

Explanation:

A Network-based intrusion detection system (NIDS) with anomaly detection
Lateral movement occurs when attackers move from one compromised system to another within a network, often seeking higher privileges or sensitive data. A NIDS with anomaly detection is effective because it monitors network traffic patterns across segments and identifies unusual behaviors that deviate from baseline activity. Examples include unexpected SMB or RDP connections between systems that normally do not communicate, or abnormal traffic flows indicative of privilege escalation attempts. Traditional signature-based systems might not detect novel lateral movement techniques, but anomaly detection allows analysts to uncover stealthy attacks. Analysts can then correlate these anomalies with logs from endpoints, servers, and SIEMs to confirm compromise and prevent further spread. Effective lateral movement detection often involves behavioral analysis, correlation of authentication events, and monitoring of administrative privileges.

B Firewall rules blocking inbound traffic
Firewalls are effective at restricting access from external sources, but lateral movement occurs internally, often bypassing firewall protections within a segmented network. While internal firewalls may help, static rules alone are insufficient to detect dynamic or sophisticated lateral movement techniques.

C Antivirus signature updates
Antivirus relies on known malware signatures. Lateral movement techniques may not involve traditional malware, especially if attackers use legitimate administrative tools (Living off the Land techniques). Signature-based AV alone cannot detect these behaviors.

D Phishing simulations
Phishing simulations help train employees to recognize malicious emails and prevent initial compromise, but they do not detect internal attacker movement. They are preventative and educational but unrelated to monitoring lateral movement.

Question 18
A security analyst is reviewing SIEM logs and notices several alerts indicating privilege escalation attempts on a critical server. Which of the following should be the analyst’s first response?

A) Conduct a forensic investigation and preserve logs
B) Immediately reboot the server
C) Deploy antivirus updates
D) Notify HR about suspicious activity

Answer A

Explanation:

A Conduct a forensic investigation and preserve logs
Privilege escalation attempts indicate that an attacker or malware is attempting to gain higher-level access to systems, which could lead to data compromise or system control. The first step is to preserve forensic evidence, including SIEM logs, system logs, and memory captures, to determine the nature of the attempt, the source, and the potential scope of compromise. Investigating logs helps identify whether the escalation was successful and whether further remediation is needed. Premature actions such as rebooting could destroy volatile data, compromising evidence collection and subsequent incident response. Proper forensic procedures include documenting findings, maintaining chain-of-custody, and correlating logs across related systems to understand attacker tactics. This approach ensures accurate incident reporting and supports regulatory compliance while enabling effective remediation strategies.

B Immediately reboot the server
Rebooting may disrupt ongoing attacks temporarily but risks losing volatile data such as memory-resident processes, open connections, and temporary system logs. This can hinder investigation and reduce the ability to understand attacker behavior.

C Deploy antivirus updates
Antivirus updates may improve detection against known threats but do not address the immediate priority of securing the server or preserving forensic evidence during a potential compromise.

D Notify HR about suspicious activity
HR involvement may be necessary if insider threat is suspected, but immediate response should prioritize containment, evidence preservation, and technical analysis. Notification is a secondary action after initial investigation steps.

Question 19
Which of the following log sources provides the best insight into potential insider threats within a corporate environment?

A) Firewall logs
B) Endpoint logs and user activity logs
C) IDS/IPS alerts
D) Vulnerability scanner reports

Answer B

Explanation:

A) Firewall Logs

Firewall logs record connections between internal and external networks. They capture valuable information such as allowed/blocked traffic, source and destination IP addresses, ports, and protocols. While these logs are essential for detecting external threats, scanning activity, or unauthorized outbound connections, they have limited usefulness for insider threat detection.

Insiders rarely need to bypass firewalls, because they already operate inside the network perimeter. Their malicious activity—such as accessing sensitive data, modifying files, or escalating privileges—occurs within internal systems where firewall logs have minimal visibility. Although firewall logs might reveal data exfiltration attempts (for example, large uploads to an external cloud service), they usually lack context about which user performed the action or what resources they interacted with beforehand. This makes firewall logs insufficient as a primary source for insider threat detection.

B) Endpoint Logs and User Activity Logs

Endpoint logs (such as Windows Event Logs, EDR telemetry, syslogs, application logs, and authentication logs) capture detailed, granular activity originating directly from user devices and systems. User activity logs include events such as:

File access and modification

Privilege escalation attempts

Login and logout times

Lateral movement across systems

Execution of unusual or unauthorized applications

Use of removable storage or unauthorized USB devices

Copying, compressing, or transmitting sensitive files

Accessing data outside of normal job functions

Attempts to disable security tools

These logs provide behavioral context that is essential for uncovering insider threats—whether negligent, compromised, or malicious.

Security analysts can correlate endpoint logs with identity and access management (IAM) logs, authentication logs, and data access logs to identify patterns such as:

Repeated access to sensitive data outside normal working hours

Downloading or copying large datasets without a business need

Attempts to access systems or files unrelated to the user’s role

Sudden privilege elevation or accessing admin tools unexpectedly

Insider threats often show subtle behavioral anomalies that only endpoint-level visibility can reveal. Tools such as EDR (Endpoint Detection and Response), UEBA (User and Entity Behavior Analytics), and SIEM platforms rely heavily on endpoint and user activity logs to create baselines and detect deviations. For this reason, Option B is the most effective and comprehensive source of insight for identifying insider threats.

 

C) IDS/IPS Alerts

Intrusion Detection Systems and Intrusion Prevention Systems detect suspicious or malicious network activity by examining packets and traffic patterns. While IDS/IPS tools are effective for discovering malware, network intrusions, and command-and-control communications, they are not designed to monitor internal user behavior at the application or endpoint level.

Insider threats often involve legitimate credentials used in legitimate sessions, making IDS/IPS much less effective for identifying them. Although IDS/IPS alerts can supplement an investigation by highlighting unusual network behavior, they lack the depth required to track user-level or file-level activity.

D) Vulnerability Scanner Reports

Vulnerability scanners assess weaknesses such as outdated software, misconfigurations, or unpatched systems. These reports are excellent for risk management but offer no visibility into day-to-day user behavior.

Insider threats are behavioral and activity-driven—not vulnerability-driven. Therefore, vulnerability reports do not provide meaningful indicators of insider activity or intent.

Question 20
A security analyst discovers a new malware variant that encrypts files and leaves a ransom note. Which of the following controls would be most effective in preventing this type of incident in the future?

A) Regular system backups and offline storage
B) Network segmentation
C) SIEM alert tuning
D) Endpoint antivirus signature updates

Answer A

Explanation:

A Regular system backups and offline storage

 Ransomware encrypts files, making them inaccessible. Maintaining regular backups stored offline ensures that organizations can restore affected systems without paying ransom. Offline storage prevents malware from accessing backup files, which is critical because ransomware often attempts to encrypt connected backups. This control is preventive in maintaining data integrity and continuity, allowing rapid recovery. Backups, combined with other defenses, mitigate operational impact even if initial infection occurs. They also reduce attacker leverage and improve organizational resilience.
Regular system backups are considered one of the most foundational safeguards because they provide a final layer of defense when all other protective measures fail. Many ransomware variants now include logic to actively seek out backup directories, cloud-sync folders, connected NAS devices, or mapped network drives in order to corrupt or encrypt them. This means online backups or backups stored on directly reachable systems may still be vulnerable. Offline backups, however, are physically or logically separated in a manner that prevents the malware from gaining access. This includes using air-gapped systems, removable media stored separately, or immutable cloud backups configured to be read-only once written.
In addition to enabling recovery, offline backups strengthen incident response by providing a stable baseline to compare against infected systems. Analysts can verify file integrity, determine the scope of tampering, and rebuild clean systems with confidence. Furthermore, backup policies that include frequent snapshots, retention periods, and redundancy across multiple geographic locations help organizations mitigate sophisticated attacks that attempt to encrypt or destroy data slowly over time. When combined with proper backup testing, documentation, and disaster-recovery planning, offline storage becomes a critical resilience mechanism.
This approach not only prevents the organization from being forced to pay ransom but also supports regulatory compliance by ensuring that essential business functions can be restored in accordance with industry standards. While preventing every ransomware intrusion is impossible due to continually evolving threat landscapes, having dependable offline backups ensures that the impact of an infection is minimized, operational downtime is reduced, and the financial motivation for attackers is significantly weakened. Over time, consistent use of verified offline backups reduces the profitability of ransomware campaigns, providing long-term strategic value beyond immediate incident recovery.

B Network segmentation

 Segmentation limits the spread of malware but does not prevent initial infection or data encryption on unsegmented systems. It is a complementary control but not sufficient as a primary mitigation.
Network segmentation plays an important role in reducing lateral movement once ransomware infiltrates the environment, but it does not directly prevent ransomware from executing on systems. For example, a workstation infected via phishing will still experience file encryption even if the network is segmented. Segmentation is more focused on containment rather than prevention. If an infected host attempts to propagate the ransomware to other systems, segmentation barriers may stop the outbreak from reaching servers or critical assets. However, this assumes the segmentation is properly configured, routinely audited, and enforced with least-privilege principles. Many organizations implement segmentation in theory but fail to enforce granular access control, allowing malware to bypass poorly structured network boundaries.
Additionally, segmentation does not stop ransomware from affecting local system data or mapped cloud storage, which are common targets. While segmentation is valuable, especially in modern zero-trust architectures, it cannot replace recovery-focused strategies like backups. Its effectiveness also depends heavily on the complexity of the network environment, administrative discipline, and monitoring. In summary, segmentation is a necessary component of layered defense but cannot serve as the primary control to prevent the operational impact of file-encrypting malware.

C SIEM alert tuning

SIEMs help detect ongoing malware activity, but alerts do not prevent files from being encrypted. SIEM tuning improves detection but does not inherently provide prevention or recovery capabilities. A SIEM system correlates logs from various sources, detecting suspicious events and providing alerts when anomalous behavior occurs, such as mass file modifications, suspicious process execution, or unauthorized privilege escalation. While a well-tuned SIEM is essential for early detection and rapid response, it is not designed to block or reverse ransomware encryption. At best, detection may happen early enough to manually isolate systems before extensive damage occurs, but this assumes the incident response team reacts quickly and has the necessary authority to take action.
SIEM tuning improves fidelity of alerts, reduces false positives, and may reveal ransomware precursor behaviors like credential harvesting or lateral movement. However, detection tools rarely intervene autonomously unless paired with integrated SOAR or EDR tools capable of automated containment. And even these may be ineffective once encryption begins. Therefore, SIEM alert tuning supports the broader security program but does not and cannot ensure recovery from a ransomware attack. Without offline backups, organizations remain vulnerable to permanent data loss regardless of detection capability.

D Endpoint antivirus signature updates

 Antivirus can block known ransomware strains, but new variants may evade signature-based detection. While AV is important, relying solely on signatures is insufficient to prevent novel ransomware infections.
Signature-based antivirus is reactive, relying on known malware indicators stored in signature databases. Attackers frequently modify ransomware code to bypass signature detection, producing variants that appear new to security tools. This results in signature-based approaches missing “zero-day” variants until updates become available. Even behavior-based detection, while more capable, may fail to recognize novel attack patterns or custom-built malware designed for a specific organization.
Modern ransomware campaigns often employ techniques such as obfuscation, packers, fileless execution, and use of legitimate administrative tools like PowerShell to avoid detection. Antivirus remains a useful component of endpoint protection, and frequent updates improve detection of established ransomware families. However, it is not sufficient as a primary defense because it does not guarantee prevention of encryption or data destruction. This is why organizations must rely on a multi-layered defense model with backups serving as the final safety net. Antivirus helps reduce infection likelihood but cannot replace the need for reliable recovery mechanisms.