GCIA Intrusion Detection Systems (IDS) and Security Information and Event Management (SIEM)

Question 1

Which type of IDS is designed to monitor network traffic and detect malicious activity by analyzing packet data?

Accepted Answer

Network-based IDS

Answer

A Network-based Intrusion Detection System (NIDS) monitors network traffic for suspicious activity or policy violations by analyzing packet data as it traverses the network. Unlike host-based IDS which monitors individual systems, a NIDS is strategically placed at network choke points to observe traffic across multiple hosts and segments. This allows it to detect threats that affect the network as a whole.

Question 2

What is the primary function of a SIEM system in network security?

Accepted Answer

To collect, aggregate, and analyze security event data

Answer

A Security Information and Event Management (SIEM) system is designed to provide real-time analysis of security alerts generated by network hardware and applications. Its primary function is to collect security logs and event data from various sources, aggregate them, and then apply correlation rules and analytics. This process identifies potential security incidents, offering a centralized view for threat detection and compliance.

Question 3

Which of the following is a common method used by IDS systems to reduce false positives?

Accepted Answer

Applying correlation rules

Answer

IDS systems often generate a high volume of alerts, many of which can be false positives. Applying correlation rules helps reduce these false positives by analyzing multiple events from different sources to determine if they collectively indicate a true threat. Instead of alerting on single suspicious events, correlation looks for patterns or sequences of events that are more indicative of malicious activity, improving alert accuracy.

Question 4

Which log source would provide information about user login attempts and authentication events?

Accepted Answer

Authentication logs

Answer

Authentication logs specifically record events related to user login attempts, successful and failed authentications, session management, and access control decisions. These logs are crucial for security monitoring as they provide direct evidence of who is attempting to access systems and whether those attempts are legitimate or malicious. They are a primary source for investigating unauthorized access.

Question 5

Which type of analysis involves comparing current network traffic patterns to established baselines to detect anomalies?

Accepted Answer

Statistical analysis

Answer

Statistical analysis in network traffic involves establishing a baseline of normal network behavior and then using statistical methods to identify deviations or anomalies from that baseline. By comparing current traffic patterns (e.g., volume, protocol usage, connection rates) against historical data, this method can detect unusual activities that might indicate a security incident or performance issue. It's a key component of behavior-based detection.

(GCIA) GIAC Certified Intrusion Analyst Practice Test

(GCIA) GIAC Certified Intrusion Analyst Practice Test

GCIA Intrusion Detection Systems (IDS) and Security Information and Event Management (SIEM)