CompTIA CS0-003  CySA+ Exam Dumps and Practice Test Questions Set 3 Q 41-60

Visit here for our full CompTIA CS0-003 exam dumps and practice test questions.

Question 41

A threat hunter discovers a workstation repeatedly initiating DNS requests to domains with randomized, nonhuman-readable names. Analysis suggests the host may be infected with malware using a domain generation algorithm (DGA). What is the FIRST action the analyst should take?

A) Quarantine the host to prevent further malicious communication
B) Deploy a DGA detection system across the network
C) Notify the ISP to block outbound DNS traffic
D) Monitor DNS traffic for six months for additional anomalies

Answer A

Explanation:

A Quarantine the host to prevent further malicious communication

DGAs generate pseudo-random domains to allow malware to communicate with command-and-control servers while evading static indicators. The workstation actively communicating with these domains indicates a compromise. Quarantining the host immediately stops exfiltration, prevents additional malware downloads, and reduces the risk of lateral movement. Containment also preserves forensic evidence needed to analyze the malware, determine its capabilities, and understand the scope of compromise. Immediate isolation aligns with incident response best practices: contain first, analyze second, remediate third.

B Deploy a DGA detection system across the network

Deploying detection tools is proactive for future attacks but does not stop ongoing malicious activity on the infected host.

C Notify the ISP to block outbound DNS traffic

 Blocking DNS traffic at the ISP level is disruptive, may impact business operations, and is not a targeted solution.

D Monitor DNS traffic for six months for additional anomalies

Monitoring alone does not prevent current malicious communications or mitigate risk.

Question 42

A security engineer detects unusual PowerShell scripts executing on multiple endpoints. The scripts are encoded and connect to external IP addresses. Traditional antivirus scans do not detect any threats. Which of the following BEST describes the nature of this attack?

A) Fileless malware leveraging living-off-the-land techniques
B) Standard ransomware with encrypted payloads
C) Phishing-based malware with email attachments
D) A denial-of-service attack targeting internal systems

Answer A

Explanation:

A Fileless malware leveraging living-off-the-land techniques

 Fileless malware does not rely on traditional files on disk; it executes in memory using legitimate tools like PowerShell, WMI, or macros to carry out malicious activity. By leveraging built-in system utilities, the malware avoids detection by traditional signature-based antivirus solutions. Indicators include obfuscated scripts, unusual command execution, and outbound connections to suspicious domains. Fileless attacks are particularly dangerous because they can escalate privileges, exfiltrate data, or download additional malware without leaving artifacts on disk, making containment and remediation challenging. Understanding these behaviors is essential for SOC teams to develop behavioral detection rules and memory-based forensic techniques.

B Standard ransomware with encrypted payloads

Ransomware typically encrypts files and drops ransom notes. While it may use malware executables, it is not inherently fileless and would be detected through standard endpoint scanning.

C Phishing-based malware with email attachments

 Phishing delivers malware via email. In this scenario, the infection is already active and executing encoded scripts, not delivered via attachments.

D A denial-of-service attack targeting internal systems

DoS attacks impact availability; they do not explain script execution or outbound connections to external IPs.

Question 43

A company’s cloud storage bucket containing sensitive customer information is accidentally set to allow public read access. Which of the following controls would MOST effectively prevent similar incidents in the future?

A) Implement automated cloud configuration monitoring with alerting
B) Require TLS for all connections to the cloud environment
C) Rotate access keys monthly
D) Conduct quarterly penetration tests

Answer A

Explanation:

A Implement automated cloud configuration monitoring with alerting

Automated configuration monitoring continuously evaluates cloud resources against defined security baselines. This includes detecting publicly accessible storage buckets, overly permissive IAM policies, or misconfigured access controls. Alerts enable immediate remediation, preventing exposure of sensitive data. Cloud Security Posture Management (CSPM) solutions are often used to enforce these policies and maintain compliance. Automation reduces human error in complex cloud environments and ensures proactive security by preventing misconfigurations before they result in data breaches.

B Require TLS for all connections to the cloud environment

TLS encrypts data in transit but does not prevent accidental public read access to storage objects.

C Rotate access keys monthly

Key rotation limits long-term credential exposure but does not prevent misconfigured permissions.

D Conduct quarterly penetration tests

 Penetration testing identifies vulnerabilities periodically but does not provide continuous, proactive monitoring for misconfigurations.

Question 44

 An organization’s file servers were encrypted by ransomware. Offline backups exist and restoration procedures have been tested. Which of the following statements BEST describes the benefit of these offline backups?

A) They allow recovery without paying the ransom, reducing operational impact
B) They prevent ransomware from spreading to endpoints
C) They detect ransomware infections before execution
D) They eliminate the need for network segmentation

Answer A

Explanation:

A They allow recovery without paying the ransom, reducing operational impact

Offline backups provide a secure, isolated recovery point that ransomware cannot access. After an attack, organizations can restore encrypted files from these backups without paying ransom, minimizing downtime, and ensuring continuity of operations. Regularly tested backups ensure recovery procedures are effective and that critical data can be restored quickly. Offline or air-gapped backups protect against ransomware attempts to encrypt connected storage. They also reduce attackers’ leverage and support compliance with data protection standards.

B They prevent ransomware from spreading to endpoint

 Backups do not stop infection propagation; they are a post-incident recovery mechanism.

C They detect ransomware infections before execution

 Backups do not provide detection or alerting capabilities.

D They eliminate the need for network segmentation

 Segmentation remains important to limit malware spread and protect other systems; backups do not replace network controls.

Question 45

A security analyst notices multiple alerts for anomalous outbound SMTP traffic from several internal endpoints. The messages contain unusual attachments and are being sent to unknown external domains. Which of the following BEST describes the threat and the first step in mitigation?

A) Spam propagation; implement email filtering rules
B) Data exfiltration via email; isolate affected endpoints
C) Phishing campaign; educate users
D) Outbound port scanning; block outbound traffic

Answer B

Explanation:

A Spam propagation; implement email filtering rules

Spam propagation typically involves sending bulk unsolicited emails to many recipients. While email filtering rules can reduce the volume of spam, this does not address the underlying compromise in this scenario. The anomalous outbound SMTP traffic originates from multiple internal hosts, suggesting these endpoints are compromised and actively exfiltrating data rather than merely sending spam. Spam filtering is reactive and will not stop ongoing malicious activity at the endpoint level.

B Data exfiltration via email; isolate affected endpoints

The pattern described—unusual attachments sent from internal endpoints to unknown external domains—strongly indicates data exfiltration. Attackers often leverage SMTP to stealthily extract sensitive files because email traffic is usually allowed through firewalls and may evade basic monitoring. The first step in mitigation is to isolate the affected endpoints to prevent further exfiltration while preserving forensic evidence. Containment halts the active threat and enables detailed investigation, including identifying the type of data exfiltrated, how the malware operates, and the extent of compromise. Analysts can then remediate the endpoints, strengthen monitoring, and implement preventive controls such as DLP policies or email gateway inspections to block unauthorized data transfers.

C Phishing campaign; educate users

While phishing campaigns often target users to deliver malicious attachments or steal credentials, the scenario describes outbound traffic already generated by internal hosts. This is post-compromise activity, not initial user exploitation. User education alone does not address the active exfiltration.

D Outbound port scanning; block outbound traffic

Port scanning involves probing hosts or services to discover vulnerabilities. SMTP traffic with attachments does not align with port scanning behavior. Blocking outbound traffic broadly may disrupt operations but does not precisely remediate the ongoing data exfiltration from compromised systems.

Question 46

A company’s security team is planning to implement a threat-hunting program. Which of the following approaches is MOST effective in identifying unknown advanced threats?

A) Utilizing signature-based antivirus logs
B) Performing behavioral analysis and anomaly detection
C) Conducting annual vulnerability scans
D) Reviewing firewall deny logs

Answer B

Explanation:

A Utilizing signature-based antivirus logs

Signature-based antivirus relies on known threat signatures to detect malware. While helpful for identifying known threats, this approach is ineffective against unknown or zero-day attacks, advanced persistent threats (APTs), or fileless malware that lacks existing signatures. Relying solely on signature detection is reactive and may leave the organization blind to sophisticated adversaries using novel techniques.

B Performing behavioral analysis and anomaly detection

Behavioral analysis and anomaly detection enable proactive threat hunting by identifying patterns that deviate from normal activity, regardless of whether malware signatures exist. Techniques include monitoring unusual process execution, abnormal network traffic flows, privilege escalation attempts, or unexpected access to sensitive data. Analysts can establish baselines of normal behavior and use machine learning or statistical models to highlight anomalies indicative of malicious activity. This approach is particularly effective against advanced persistent threats, stealthy malware, and insider threats, as it focuses on actions rather than relying on known indicators. By correlating telemetry across endpoints, network devices, and cloud platforms, security teams can uncover previously unknown threats before they cause significant damage. Behavioral threat hunting also supports continuous improvement by providing feedback for tuning detection rules, enriching threat intelligence, and guiding response strategies.

C Conducting annual vulnerability scans

Annual scans are periodic and provide insight into potential weaknesses, but they are not real-time and do not detect active or unknown threats. Vulnerability scanning is a preventative measure, not a hunting technique.

D Reviewing firewall deny logs

 Firewall deny logs provide visibility into blocked network traffic but only reveal known policy violations. They rarely indicate advanced or stealthy attacker activity and are insufficient for identifying unknown threats.

Question 47

A security analyst identifies repeated login attempts to a database server using a high volume of different usernames over an extended period. The attack is distributed across multiple source IP addresses. Which of the following controls would MOST effectively mitigate this type of attack?

A) Implementing multi-factor authentication
B) Increasing password complexity requirements
C) Blocking outbound database connections
D) Enabling verbose logging

Answer A

Explanation:

A Implementing multi-factor authentication

The described attack is a credential-stuffing attempt, where attackers use lists of usernames and passwords to gain unauthorized access. Multi-factor authentication (MFA) effectively mitigates this attack because possession of the password alone is insufficient to gain access. MFA requires a second factor—such as a one-time token, mobile push approval, or biometric factor—which attackers cannot easily compromise in a distributed brute-force scenario. Implementing MFA for administrative and database accounts dramatically reduces the likelihood of successful account compromise and improves overall resilience against credential-based attacks.

B Increasing password complexity requirements

Complex passwords reduce the chance of guessing credentials but do not prevent attacks against reused or stolen credentials. MFA is more effective against distributed attacks.

C Blocking outbound database connections

 Blocking outbound traffic does not prevent inbound login attempts. The threat involves external access to the database, so restricting outbound traffic is irrelevant.

D Enabling verbose logging

Verbose logging aids investigation and detection but does not prevent attacks. Logging is reactive and does not stop ongoing credential abuse.

Question 48

A cybersecurity team discovers a misconfigured cloud storage bucket that allows public read access. The bucket contains sensitive organizational data. Which of the following controls would MOST effectively prevent future misconfigurations?

A) Implement automated cloud configuration monitoring and alerting
B) Enable TLS for all data in transit
C) Rotate all access keys monthly
D) Conduct quarterly penetration tests

Answer A

Explanation:

A Implement automated cloud configuration monitoring and alerting

Automated configuration monitoring continuously evaluates cloud resources against security baselines, detecting misconfigurations such as publicly accessible buckets or overly permissive IAM policies. Alerts allow immediate remediation before sensitive data exposure occurs. Tools like Cloud Security Posture Management (CSPM) solutions can identify deviations from best practices, enforce policy compliance, and prevent inadvertent data leakage. Automation ensures scalability in complex cloud environments and reduces human error in configuration management. By continuously monitoring settings, organizations can maintain strong security posture, detect misconfigurations promptly, and prevent breaches caused by accidental exposure.

B Enable TLS for all data in transit

TLS protects data during transmission but does not prevent misconfigured permissions that allow public access.

C Rotate all access keys monthly

 Key rotation is useful for limiting long-term exposure but does not prevent misconfigurations or accidental public access.

D Conduct quarterly penetration tests

Pen tests are periodic and may identify exposures, but they do not provide continuous monitoring or proactive prevention of misconfigurations.

Question 49

An organization experiences a ransomware attack that encrypts multiple file servers. The organization’s recovery plan includes offline backups and tested restoration procedures. Which of the following statements BEST describes the impact of the offline backups in this scenario?

A) They allow recovery without paying the ransom, reducing operational impact
B) They prevent the ransomware from spreading to endpoints
C) They detect ransomware infections before execution
D) They eliminate the need for network segmentation

Answer A

Explanation:

A They allow recovery without paying the ransom, reducing operational impact

Offline backups provide a resilient recovery mechanism. When ransomware encrypts files, backups stored offline or in air-gapped locations remain unaffected, allowing the organization to restore data to a clean state without engaging with attackers. This minimizes downtime, ensures continuity of operations, and removes the financial leverage attackers gain through ransom demands. Offline backups are a critical control in incident response and business continuity, enabling organizations to recover quickly even in worst-case scenarios. By combining offline backups with frequent testing, retention policies, and offsite storage, organizations can fully mitigate the operational and financial impact of ransomware incidents.

B They prevent the ransomware from spreading to endpoints

Backups do not stop active infection or lateral movement; they are a post-incident recovery mechanism.

C They detect ransomware infections before execution

 Offline backups are not a detection mechanism. Detection requires monitoring tools, endpoint protection, and behavioral analysis.

D They eliminate the need for network segmentation

Segmentation reduces spread but remains necessary as part of defense-in-depth; backups do not replace network controls.

Question 50

A security analyst observes that attackers have exploited a web server vulnerability to execute arbitrary code and deploy a reverse shell. After containment, the analyst must understand the root cause and prevent recurrence. Which of the following actions is MOST effective for preventing future attacks of this type?

A) Conduct secure code review and deploy application-layer input validation
B) Deploy network firewalls to block incoming traffic
C) Increase session timeout values on web applications
D) Perform vulnerability scans only quarterly

Answer A

Explanation:

A Conduct secure code review and deploy application-layer input validation

The attack exploited a vulnerability in the web application that allowed arbitrary code execution. Secure code review and robust input validation prevent similar attacks by ensuring that all input is sanitized, properly parsed, and does not interact with the system shell or sensitive APIs. Input validation enforces strict rules such as whitelisting acceptable characters, limiting parameter lengths, and rejecting unexpected data types. Combined with secure coding practices, parameterized queries, and proper error handling, these measures eliminate common attack vectors like command injection, SQL injection, and remote code execution. Conducting code reviews regularly allows developers and security teams to identify flaws before deployment, thereby strengthening security posture.

B Deploy network firewalls to block incoming traffic

 Firewalls may reduce exposure but cannot address application-level vulnerabilities exploited by authorized traffic.

C Increase session timeout values on web applications

Session timeouts help limit session hijacking but do not prevent the execution of malicious payloads.

D Perform vulnerability scans only quarterly

Quarterly scans are insufficient for proactive prevention. Critical vulnerabilities require timely identification and remediation.

Question 51

A SOC analyst notices repeated outbound HTTP requests from an internal server to a domain known for hosting malware. Upon investigation, the traffic appears to be encrypted and the server is also attempting DNS queries for random subdomains. Which of the following BEST describes the type of threat?

A) Command-and-control traffic using a domain generation algorithm (DGA)
B) Denial-of-service attack
C) Phishing campaign
D) Port scanning activity

Answer A

Explanation:

A Command-and-control traffic using a domain generation algorithm (DGA)

The behavior described indicates a malware infection actively communicating with its command-and-control (C2) infrastructure. DGAs are often used to dynamically generate domain names for C2 communications, making it harder for defenders to block malicious domains. Encrypted outbound HTTP traffic prevents easy inspection of payloads, indicating covert communication. The repeated DNS queries for random subdomains are characteristic of DGAs trying to resolve attacker-controlled domains to receive commands or exfiltrate data. Detecting this activity requires correlation of DNS requests, outbound network patterns, and endpoint behaviors. The analyst should contain the affected server immediately to prevent data loss and further propagation while preserving forensic evidence for detailed analysis.

B Denial-of-service attack

DoS attacks overwhelm resources to impact availability. The scenario indicates ongoing C2 communications, not service disruption.

C Phishing campaign

Phishing targets users to steal credentials. Outbound server traffic to DGA-generated domains is unrelated to phishing.

D Port scanning activity

Port scanning probes hosts or ports to find open services. DNS queries and encrypted HTTP traffic do not match scanning behavior.

Question 52

 A company has multiple service accounts in Active Directory that have not been used for over six months but still possess administrative privileges. Which of the following controls would BEST mitigate the risk associated with these accounts?

A) Implementing an automated account deprovisioning policy
B) Enforcing password complexity requirements
C) Disabling external SSH connections
D) Deploying full disk encryption on all endpoints

Answer A

Explanation:

A Implementing an automated account deprovisioning policy

 Inactive privileged accounts represent a major security risk. They can be exploited by attackers through password guessing, credential theft, or lateral movement. Automating the deprovisioning process ensures that accounts are disabled or removed after a defined period of inactivity, reducing the attack surface. This also enforces the principle of least privilege, ensuring that administrative rights are granted only when necessary. Integration with identity governance systems and privileged access management (PAM) solutions enhances control over account lifecycle management, including timely reviews, approvals, and automated removal. By proactively managing account decommissioning, organizations prevent attackers from exploiting dormant accounts to escalate privileges or maintain persistence.

B Enforcing password complexity requirements

While complex passwords reduce the likelihood of guessing attacks, they do not address the risk posed by dormant accounts that still exist with elevated privileges.

C Disabling external SSH connections

SSH restrictions may limit access from outside networks but do not mitigate risks associated with unused internal accounts.

D Deploying full disk encryption on all endpoints

Encryption protects data at rest but does not reduce the risk posed by active, privileged accounts within the directory.

Question 53

A network monitoring tool detects multiple service accounts attempting authentication across various systems at unusual hours, suggesting possible credential abuse. Which control would MOST effectively mitigate this threat?

A) Implement multi-factor authentication for all privileged accounts
B) Increase password complexity requirements for service accounts
C) Disable logging for failed authentication attempts to reduce noise
D) Enforce longer session timeout values

Answer A

Explanation:

A Implement multi-factor authentication for all privileged account

Multi-factor authentication (MFA) adds an additional layer of security beyond passwords. Even if attackers obtain credentials for service accounts, they cannot authenticate without the second factor, such as a token, push notification, or biometric verification. MFA effectively mitigates attacks such as credential stuffing, brute-force login attempts, or post-compromise lateral movement. For service accounts with elevated privileges, implementing MFA is critical because it directly prevents unauthorized access, even if the account credentials are stolen or leaked. MFA also allows organizations to maintain operational continuity while significantly reducing the likelihood of privilege escalation and compromise of critical systems.

B Increase password complexity requirements for service accounts

 While helpful for password resilience, complex passwords alone do not stop attackers from using stolen or reused credentials.

C Disable logging for failed authentication attempts to reduce noise

Disabling logging removes visibility into attacks, undermining detection and monitoring efforts.

D Enforce longer session timeout values

Extending session durations does not prevent unauthorized authentication attempts.

Question 54

During a penetration test, testers exploit a web application vulnerability that allows them to execute OS-level commands through a poorly validated input parameter. Which control would BEST prevent this type of attack?

A) Implement server-side input validation with parameterized commands
B) Enforce TLS encryption for all web traffic
C) Increase timeout values for web sessions
D) Add more firewall rules at the perimeter

Answer A

Explanation:

A Implement server-side input validation with parameterized commands

 Command injection vulnerabilities occur when user input is improperly sanitized and passed to system-level processes. Server-side input validation ensures that all input is checked against expected patterns, types, and lengths before execution. Parameterized commands or prepared statements prevent attackers from injecting arbitrary instructions into system calls or database queries. Proper input validation also reduces the attack surface for SQL injection, OS command injection, and similar exploits. Regular code reviews, static code analysis, and secure coding practices reinforce this control. By validating input at the application layer, the organization can prevent remote code execution attacks even if the network and host are otherwise exposed.

B Enforce TLS encryption for all web traffic

 TLS secures data in transit but does not prevent command injection at the application layer.

C Increase timeout values for web sessions

 Session timeouts manage user inactivity but are unrelated to input validation or command injection prevention.

D Add more firewall rules at the perimeter

 Firewalls control network traffic and do not protect against application-layer vulnerabilities.

Question 55

A security analyst investigates a server compromise and discovers that an attacker has used stolen credentials to create a reverse shell. Which of the following controls would BEST prevent similar incidents in the future?

A) Implement privileged access management (PAM) with just-in-time access
B) Increase password complexity for all accounts
C) Deploy endpoint antivirus with updated signatures
D) Disable all remote access capabilities

Answer A

Explanation:

A Implement privileged access management (PAM) with just-in-time access

 Privileged Access Management (PAM) solutions reduce the exposure of high-privilege accounts by granting access only when required, for a limited duration, and with full session logging. Just-in-time (JIT) access ensures that credentials are not persistently available, limiting attackers’ ability to reuse stolen credentials to create reverse shells or perform lateral movement. PAM also enforces strong authentication, monitors and audits administrative actions, and reduces the attack surface associated with standing privileges. Implementing JIT PAM reduces the window of opportunity for attackers, improves accountability, and strengthens overall security posture.

B Increase password complexity for all accounts

 Complex passwords make brute-force attacks more difficult but do not prevent misuse of stolen credentials.

C Deploy endpoint antivirus with updated signatures

Antivirus may detect known malware, but reverse shells using legitimate tools or scripts may bypass signature detection entirely.

D Disable all remote access capabilities

 Disabling remote access is often operationally impractical and does not address the root cause of credential misuse; targeted controls like PAM are more effective.

Question 56

A security analyst detects repeated brute-force login attempts against an internal VPN server. The attempts originate from multiple geographic locations and use common usernames. Which of the following controls would BEST mitigate this attack?

A) Implement multi-factor authentication (MFA) for VPN access
B) Increase password complexity requirements for VPN accounts
C) Block all external VPN connections
D) Enable verbose logging on the VPN server

Answer A

Explanation:

A Implement multi-factor authentication (MFA) for VPN access

MFA adds an additional verification step beyond just the password, such as a one-time token, push notification, or biometric factor. Even if attackers have obtained or guessed credentials, they cannot gain access without the second factor. MFA is especially effective against distributed brute-force attacks that leverage credential lists or common usernames. It reduces the risk of account compromise, protects remote access services, and aligns with industry best practices for securing critical network entry points. By implementing MFA, organizations prevent unauthorized access while maintaining legitimate connectivity for remote users.

B Increase password complexity requirements for VPN accounts

 Complex passwords slow down brute-force attacks but do not prevent attackers from leveraging already stolen credentials or bypassing authentication using password lists.

C Block all external VPN connections

Blocking all VPN access would disrupt business operations and is not a targeted solution. The goal is to secure legitimate access while preventing attacks.

D Enable verbose logging on the VPN server

Logging enhances detection but does not mitigate ongoing attacks. It is reactive rather than preventive.

Question 57

A company migrates critical applications to a cloud environment. During a security review, the analyst discovers that several cloud storage buckets are publicly accessible. Which control would MOST effectively prevent accidental exposure of sensitive data?

A) Implement automated cloud configuration monitoring with alerting
B) Require encryption for all data in transit
C) Conduct quarterly penetration tests of the cloud environment
D) Rotate cloud access keys every 30 days

Answer A

Explanation:

A Implement automated cloud configuration monitoring with alerting

 Automated cloud configuration monitoring continuously scans cloud resources for misconfigurations such as publicly accessible buckets, overly permissive IAM roles, or exposed storage endpoints. By generating alerts for deviations from established security baselines, administrators can remediate risks before sensitive data is exposed. Cloud Security Posture Management (CSPM) tools are commonly used to enforce security best practices, automate compliance checks, and maintain visibility across complex cloud infrastructures. Automated monitoring reduces reliance on manual checks, mitigates human error, and ensures rapid detection of misconfigurations that could lead to data breaches.

B Require encryption for all data in transit

Encryption protects data confidentiality during transfer but does not prevent exposure caused by misconfigured permissions.

C Conduct quarterly penetration tests of the cloud environment

Penetration testing is periodic and does not provide continuous visibility into misconfigurations.

D Rotate cloud access keys every 30 days

Key rotation helps mitigate credential compromise but does not prevent misconfigurations of storage access policies.

Question 58

A SOC analyst discovers that an attacker exploited a SQL injection vulnerability in a customer-facing web application. The attacker accessed sensitive customer records, including financial data. Which of the following security controls would MOST effectively prevent this type of attack in the future?

A) Implement parameterized queries and input validation
B) Deploy network-based intrusion detection systems (NIDS)
C) Enforce TLS for all application communications
D) Enable verbose logging on the database server

Answer A

Explanation:

A Implement parameterized queries and input validation

SQL injection occurs when user-supplied input is directly inserted into database queries without proper sanitization. Parameterized queries and stored procedures ensure that input is treated as data rather than executable code, preventing attackers from manipulating SQL commands. Input validation further restricts acceptable characters, data types, and input lengths, reducing the attack surface. Secure coding practices, combined with regular code reviews and application security testing, significantly mitigate SQL injection risks. Properly implementing these controls prevents unauthorized data access, protects sensitive information, and aligns with industry security standards such as OWASP Top Ten.

B Deploy network-based intrusion detection systems (NIDS)

 NIDS may detect abnormal traffic patterns, but they do not inherently prevent application-layer SQL injection attacks.

C Enforce TLS for all application communications

 TLS protects data in transit but does not prevent malicious input from being executed on the server.

D Enable verbose logging on the database server

Logging aids in detection and forensic investigation but does not prevent attacks from occurring.

Question 59

An analyst observes that multiple internal workstations are scanning other endpoints on the network for open SMB shares and attempting authentication using default or weak credentials. Which of the following is the MOST likely cause of this activity?

A) A worm attempting lateral movement
B) Misconfigured group policies
C) Backup software querying network shares
D) File synchronization utilities running on endpoints

Answer: A

Explanation:

A worm attempting lateral movement

The scenario described is highly indicative of a self-propagating worm operating within a network environment. Worms are a subclass of malware designed to replicate themselves and spread autonomously across systems, often without requiring direct human interaction. The key behaviors noted in the question—namely, multiple internal workstations performing network scans for open Server Message Block (SMB) shares and attempting authentication using default or weak credentials—are textbook signs of lateral movement attempts by a worm.

Lateral movement is a technique used by malware and attackers to expand their foothold within a network after initial compromise. Once an endpoint is infected, the worm attempts to identify other reachable hosts by scanning common network ports and services, such as SMB, which is used for file and printer sharing in Windows environments. By targeting SMB shares specifically, the worm leverages a well-known attack vector, as SMB often contains sensitive or accessible resources that can be exploited to propagate the infection further.

The use of default or weak credentials is another critical indicator. Many worms are programmed with lists of commonly used usernames and passwords to automate the authentication process. This brute-force or credential-stuffing approach allows them to compromise additional systems without needing sophisticated exploitation of software vulnerabilities. Historically, worms like WannaCry and EternalBlue exploited SMB vulnerabilities directly, but other worms rely on credential attacks combined with network scanning to achieve propagation.

Once a worm begins scanning and attempting authentication across multiple endpoints, it can compromise a significant portion of the network in a short time. This rapid spread is dangerous because it can overwhelm network resources, compromise sensitive data, and allow attackers to establish persistent access to multiple systems simultaneously. Furthermore, worms can create secondary issues, such as the deployment of additional malware payloads, ransomware, or backdoors that provide remote access to attackers.

Detecting and containing such activity requires prompt and well-coordinated incident response actions. Initial detection often involves monitoring network traffic for anomalous patterns, such as repeated SMB connection attempts, authentication failures, or unusual scanning activity. Security operations center (SOC) teams must then isolate affected systems to prevent further lateral movement. Network segmentation can help limit the worm’s ability to reach additional endpoints. Additionally, organizations should rotate compromised or potentially compromised credentials, enforce strong password policies, and ensure multi-factor authentication is in place to mitigate the impact of credential-based attacks.

Forensic analysis is also essential. Capturing logs, endpoint snapshots, and network traffic data helps identify the worm’s origin, propagation path, and the extent of the infection. This information is crucial for eradication and remediation efforts, ensuring that all compromised systems are cleaned and security gaps are addressed to prevent future incidents.

In the combination of network-wide scanning for SMB shares and repeated authentication attempts using weak or default credentials strongly points to the presence of a self-propagating worm attempting lateral movement. This behavior is distinct from other legitimate network activities or configuration issues, which typically do not involve high-volume automated scanning or repeated authentication attempts across multiple endpoints.

Misconfigured group policies

Group policy misconfigurations can indeed affect access to network resources, including SMB shares. However, misconfigured policies typically result in access denials, permission errors, or inconsistencies in user experience rather than automated scanning and repeated authentication attempts. Misconfigurations are generally static and predictable, without the dynamic replication and propagation behavior exhibited by worms. While important to review during an incident, group policy issues alone would not explain the network-wide scanning and brute-force attempts described.

Backup software querying network shares

Backup software routinely accesses known, authorized directories to perform scheduled backups. These processes are normally predictable, and connections are made only to pre-configured targets, with valid credentials provided. Backup software does not perform high-volume scans of unknown network hosts or attempt repeated authentication with multiple credentials. Therefore, although backup operations can generate network traffic, they do not match the pattern of lateral movement and automated exploitation described.

File synchronization utilities running on endpoint

File synchronization tools, such as cloud-based sync clients, access designated directories to synchronize files across devices. While these tools do generate network traffic, they operate within authorized boundaries and authenticate using valid credentials. They do not perform large-scale scanning for unknown SMB shares or attempt multiple credential combinations. Consequently, file synchronization utilities are unlikely to be the cause of the observed activity.

  The network behavior described—automated scanning for SMB shares, repeated authentication attempts using weak or default credentials, and the involvement of multiple internal workstations—is most consistent with a worm attempting lateral movement. Proper containment, detection, and forensic procedures are critical to mitigating such threats and preventing further compromise of the network environment.

Question 60

A security analyst detects that outbound DNS traffic from a host contains unusually long TXT record requests to external domains. The analyst suspects data exfiltration via DNS tunneling. Which of the following steps should the analyst take FIRST?

A) Block suspicious DNS requests and isolate the affected host
B) Flush DNS caches across the network
C) Increase TTL values for DNS records
D) Monitor DNS traffic for the next six months

Answer: A

Explanation:

Block suspicious DNS requests and isolate the affected host

DNS tunneling is a covert communication technique used by attackers to exfiltrate data or communicate with compromised systems while bypassing traditional security controls. In this scenario, the presence of unusually long TXT record requests originating from a host to external domains strongly suggests the use of DNS as a covert channel for data exfiltration. TXT records are often abused in DNS tunneling because they can carry arbitrary text data, making them ideal for encoding information to be sent outside the network undetected.

The first priority in responding to suspected DNS tunneling is to immediately stop the malicious activity to prevent further data loss. This involves two critical actions: blocking the suspicious DNS requests and isolating the affected host. Blocking the requests can be achieved by firewall rules, DNS sinkholes, or network access controls that prevent the host from resolving or sending queries to the suspicious external domains. Isolation of the host from the rest of the network is essential to contain the incident, ensuring that sensitive data is not exfiltrated further and preventing the tunneling malware from communicating with its command-and-control infrastructure.

Isolating the host also preserves evidence, which is crucial for forensic investigation. By capturing logs, network traffic, and system snapshots before any remediation or reimaging occurs, the analyst can identify the malware involved, the type and amount of data exfiltrated, and the method of compromise. Understanding these details allows the organization to remediate the vulnerability, strengthen defenses, and potentially attribute the attack.

After containment, standard incident response steps include investigation, eradication, and recovery. Investigation involves analyzing DNS traffic, examining endpoint behavior, reviewing system logs, and identifying the malware variant. Eradication includes removing malware, closing the exploited vulnerabilities, and applying patches or security configurations. Recovery involves restoring the system to a known-good state, re-enabling network connectivity, and monitoring for any residual or recurring malicious activity.

Prompt action is crucial because DNS tunneling can transmit sensitive information rapidly. The technique can bypass conventional security measures because DNS traffic is often permitted through firewalls and considered legitimate network activity. Attackers may encode login credentials, intellectual property, internal documents, or configuration files within DNS queries. If not addressed quickly, the exfiltration can compromise sensitive corporate or customer data, potentially leading to financial loss, reputational damage, and regulatory violations.

Flush DNS caches across the network

 Flushing DNS caches does not prevent ongoing data exfiltration. DNS cache flushes merely clear local or recursive resolver caches and do not interrupt active communications from a compromised host to external domains. While it may affect legitimate caching, it is ineffective against an actively tunneling host. The malicious queries will resume immediately unless the source host is blocked or isolated.

Increase TTL values for DNS record

Increasing the Time-to-Live (TTL) value of DNS records affects caching duration and how frequently resolvers query authoritative servers. This has no impact on preventing DNS-based data exfiltration. Attackers can continue to generate long TXT record requests regardless of TTL values. Adjusting TTL is irrelevant in the context of an active data exfiltration threat.

Monitor DNS traffic for the next six months

 While long-term monitoring is useful for trend analysis and improving network visibility, it does not stop immediate exfiltration. Leaving the host connected while monitoring allows the attacker to continue transmitting sensitive data. Containment must occur first to protect the organization from additional compromise. Monitoring alone is reactive and insufficient as a primary response.

  The detection of unusually long DNS TXT records originating from a host is a strong indicator of DNS tunneling and potential data exfiltration. The FIRST action must be proactive containment: blocking the malicious DNS requests and isolating the affected host. This immediate response halts the exfiltration, preserves forensic evidence, and provides a foundation for further investigation and remediation. Subsequent steps include detailed traffic analysis, malware removal, vulnerability remediation, and monitoring for any reoccurrence to ensure complete recovery and strengthen security posture.