CS0-003 Practice Test 3 — 10 Questions

Question 1

During an incident response, the team identifies that a workstation was compromised via a phishing email. Which of the following should be performed immediately after containment?

Accepted Answer

Eradicate the malware from the workstation.. Immediately after containment, the priority is to eradicate the malware from the workstation to prevent reinfection or lateral movement. Containment isolates the system, but eradication removes the malicious artifacts (e.g., registry keys, scheduled tasks, or malicious binaries) to ensure the system is clean before recovery. This step aligns with the NIST SP 800-61 incident response lifecycle, where eradication follows containment to eliminate the threat's foothold.

Answer

Notify law enforcement about the phishing campaign.

Answer

Collect forensic evidence from the workstation.

Answer

Conduct a root cause analysis of the phishing email.

Question 2

Refer to the exhibit. The output is from a Linux system running `netstat -an`. Which of the following ports is likely being used for remote command-and-control communication?

Accepted Answer

54321. Port 54321 is a high-numbered ephemeral port that is not associated with any standard service, making it a common choice for malware or remote access tools (RATs) to establish command-and-control (C2) communication. In the netstat -an output, an established connection on a non-standard high port from the local system to a remote IP is a strong indicator of C2 activity, as legitimate services typically use well-known ports.

Answer

22

Answer

53

Answer

80

Question 3

A security analyst notices that a system is sending a large amount of data to an external IP address via DNS tunneling. Which containment technique is most appropriate?

Accepted Answer

Disconnect the system from the network. Disconnecting the system from the network (Option B) is the most appropriate containment technique because it immediately stops all data exfiltration, including DNS tunneling traffic, without relying on any other network component. DNS tunneling works by encoding data within DNS queries and responses, so simply changing DNS server settings or blocking the external IP may not stop the attack if the malware uses fallback resolvers or rotates IPs. Disconnecting the system ensures the threat is isolated at the host level, preventing further data loss while preserving forensic evidence.

Answer

Change the DNS server settings

Answer

Block the external IP at the firewall

Answer

Disable the DNS service on the system

Question 4

A company wants to automate the deployment of security patches to endpoints. Which of the following tools would BEST support this requirement?

Accepted Answer

Enterprise patch management tool. An enterprise patch management tool (e.g., Microsoft WSUS, SCCM, or Ivanti) is specifically designed to automate the deployment, scheduling, and reporting of security patches across endpoints. It directly addresses the requirement by pushing patches to systems based on policy, ensuring compliance, and reducing manual effort.

Answer

Vulnerability scanner

Answer

Configuration management tool

Answer

Security information and event management (SIEM) system

Question 5

During forensic acquisition, which of the following types of data is considered the MOST volatile?

Accepted Answer

RAM.. RAM (Random Access Memory) is the most volatile data because it loses its contents immediately when power is removed. In forensic acquisition, the order of volatility dictates that RAM must be captured first, as it contains running processes, open network connections, and decrypted data that cannot be recovered from disk. Network connections, while volatile, are a subset of the data stored in RAM and are less critical to capture first.

Answer

Network connections.

Answer

Disk.

Answer

Page file.

Question 6

An analyst needs to identify which process on a Windows system is making outbound connections to the internet. Which tool should be used?

Accepted Answer

Resource Monitor. Resource Monitor (resmon.exe) provides a real-time view of network activity, including which processes are making outbound TCP and UDP connections, along with the remote addresses and ports. Unlike netstat, it directly associates network connections with specific process names and allows filtering by process, making it the most efficient tool for identifying the exact process responsible for outbound internet traffic.

Answer

netstat -an

Answer

Task Manager

Answer

Performance Monitor

Question 7

A security analyst at a financial institution is responsible for vulnerability management. The company has a policy that all critical vulnerabilities must be remediated within 72 hours. The weekly vulnerability scan identifies a critical vulnerability on a file server that hosts sensitive customer data. The vulnerability is a remote code execution in the operating system. The server is running a legacy OS that is no longer supported by the vendor. The system owner states that the application on the server cannot be migrated to a newer OS for at least six months. The server cannot be taken offline because it is used by the compliance team for daily audits. Which of the following should the analyst recommend to best address the risk?

Accepted Answer

Implement compensating controls such as network segmentation and host-based firewall rules.. When a critical vulnerability cannot be patched due to legacy OS constraints, compensating controls are the best approach to reduce risk. Network segmentation isolates the server from untrusted hosts, and host-based firewall rules restrict inbound/outbound traffic to only necessary ports and IPs, mitigating the remote code execution vector without taking the server offline.

Answer

Remove the server from the network immediately.

Answer

Accept the risk and document the exception.

Answer

Apply a custom patch developed by the manufacturer.

Question 8

A SOC analyst notices a spike in outbound traffic from a server that normally only serves web pages. The signature-based IDS did not alert. What should the analyst do next?

Accepted Answer

Query threat intelligence for the destination IPs. Querying threat intelligence for the destination IPs is the correct next step because the spike in outbound traffic from a web server suggests a potential data exfiltration attempt or command-and-control (C2) communication. Since the signature-based IDS did not alert, the traffic may be using non-standard ports or encrypted channels that evade known signatures. Threat intelligence can reveal if the destination IPs are associated with known malicious actors, botnets, or recent threat campaigns, providing context to determine if the traffic is benign or malicious.

Answer

Disable the server immediately

Answer

Check for zero-day vulnerabilities

Answer

Increase the IDS sensitivity threshold

Question 9

During a containment phase of an incident response, the team needs to prevent an infected host from communicating with a command-and-control server. The host is a critical database server that cannot be taken offline. Which of the following containment strategies is most appropriate?

Accepted Answer

Block the C2 IP at the firewall. Blocking the C2 IP at the firewall is the most appropriate strategy because it disrupts the command-and-control communication without taking the critical database server offline. This network-layer containment allows the host to continue serving its database functions while preventing outbound traffic to the malicious IP, aligning with the need for a surgical containment approach.

Answer

Pull the network cable

Answer

Disable the database service

Answer

Isolate the host by VLAN

Question 10

During forensic analysis of a compromised server, the analyst finds that the attacker deleted the system logs. Which data source is most likely to still contain relevant evidence?

Accepted Answer

Endpoint detection and response (EDR) telemetry. EDR telemetry is the most reliable source because it captures process creation, network connections, file modifications, and registry changes in real-time, storing them off-host. Even if an attacker deletes local system logs, the EDR agent's telemetry stream remains intact on the central management server, providing a forensic timeline of the attacker's actions.

Answer

Memory dump from before the attack

Answer

Network flow logs

Answer

Backup tapes