Signature-Based IDS Overview Answers 1. What is a characteristic feature of signatures used in detection systems? A. They include specific sequences of network packets. B. They only rely on known malware names. C. They are uniform across all system architectures. D. They only trigger alerts based on user behavior. Answer: They include specific sequences of network packets. (A) Signatures can include specific sequences of network packets as part of their identification techniques. 2. How does the performance impact of signature matching typically vary? A. It only affects the systems subject to IDS positively. B. It has no effect on network performance. C. It always leads to a decrease in system performance. D. It can vary based on the complexity of the system. Answer: It can vary based on the complexity of the system. (D) The performance impact of signature matching can vary and may be substantial in complex systems. 3. Why are signature-based IDS typically used in conjunction with other detection methods? A. They cannot effectively combat sophisticated and unknown attacks. B. They can only identify unknown attacks. C. They rely solely on user authentication data. D. They are less efficient at detecting known threats. Answer: They cannot effectively combat sophisticated and unknown attacks. (A) Signature-based IDS offer valuable detection for known threats but have limitations against sophisticated attacks, necessitating additional methods. 4. What factors influence the accuracy of a signature-based IDS? A. The user’s familiarity with the system. B. The quality of the threat intelligence information. C. The geographical location of the server. D. The time of day when the system is active. Answer: The quality of the threat intelligence information. (B) The accuracy of signature-based IDS heavily depends on the quality of the implemented threat intelligence information. 5. What can be included in the design of a signature to improve threat identification? A. Static responses to events instead of dynamic analysis. B. Only recent malware signatures for efficiency. C. Multiple parameters for identifying unknown sources. D. A single parameter for streamlined processing. Answer: Multiple parameters for identifying unknown sources. (C) Signatures may include multiple parameters to aid with threat identification from unknown sources. 6. What is the primary function of a signature-based intrusion detection system? A. To ignore known threats for system performance B. To block all incoming network traffic C. To compare network traffic against known attack patterns D. To create new attack patterns Answer: To compare network traffic against known attack patterns (C) A signature-based IDS identifies malicious activity by comparing current network traffic or events with a database of known patterns. 7. What triggers an alert in a signature-based IDS? A. Outdated security software on the system B. A match between observed events and predefined signatures C. Unusual user behavior detected over time D. An increase in overall network traffic Answer: A match between observed events and predefined signatures (B) An alert is triggered when there is a match between the observed events and the predefined signatures stored in the database. 8. Why does the effectiveness of a signature-based IDS rely on its signature database? A. The size of the database directly relates to system speed B. The database must include only recent threats C. The database can be static with no updates needed D. The quality and comprehensiveness of signatures determine detection ability Answer: The quality and comprehensiveness of signatures determine detection ability (D) The effectiveness of a signature-based IDS is heavily dependent on the quality and regular updates of its signature database. 9. Which of the following is an advantage of using signature-based intrusion detection systems? A. Complete independence from threat intelligence feeds B. Reduction in false positives due to refined algorithms C. Ability to detect both known and unknown threats D. Simplicity in implementation and understanding Answer: Simplicity in implementation and understanding (D) Signature-based IDS are relatively simple to implement and understand, making them accessible for many organizations. 10. What is a significant disadvantage of signature-based IDS? A. Inability to detect known threats efficiently B. Prevention of all network traffic C. Poor detection of unknown or sophisticated attacks D. Dependence on static attack patterns without updates Answer: Poor detection of unknown or sophisticated attacks (C) Signature-based IDS struggle to detect unknown or sophisticated attacks that have not been observed or documented yet. 11. How often should the signature database of a signature-based IDS be updated? A. Immediately after any detected intrusion B. Regularly, to keep up with new and evolving threats C. Only once a year during audits D. Never, once it is established Answer: Regularly, to keep up with new and evolving threats (B) The signature database requires regular updates to remain effective against new threats or variations of existing ones. 12. What type of false event may a signature-based IDS frequently trigger? A. False negatives for well-documented threats B. False positives due to benign activities resembling malicious patterns C. No alerts for known attack signatures D. False data corruption of the signature database Answer: False positives due to benign activities resembling malicious patterns (B) Signature-based IDS may generate a high number of false positives, incorrectly triggering alerts when non-malicious activity resembles known malicious patterns. 13. What aspect of an IDS significantly affects its detection capabilities? A. The complexity of the algorithms used B. The quality and timeliness of threat intelligence feeds C. The types of hardware used for the installation D. The number of users accessing the system Answer: The quality and timeliness of threat intelligence feeds (B) Detection heavily relies on the quality and timeliness of threat intelligence feeds that support the signature database.