CompTIA Security+ Question H-82

Suspicious traffic without a specific signature was detected. Under further investigation, it was determined that these were false indicators. Which of the following security devices needs to be configured to disable future false alarms?

A. Signature based IPS
B. Signature based IDS
C. Application based IPS
D. Anomaly based IDS

Answer: D

Explanation:
Most intrusion detection systems (IDS) are what is known as signature-based. This means that they operate in much the same way as a virus scanner, by searching for a known identity – or signature – for each specific intrusion event. And, while signature-based IDS is very efficient at sniffing out known s of attack, it does, like anti-virus software, depend on receiving regular signature updates, to keep in touch with variations in hacker technique. In other words, signature-based IDS is only as good as its database of stored signatures. Any organization wanting to implement a more thorough – and hence safer – solution, should consider what we call anomaly-based IDS. By its nature, anomaly-based IDS is a rather more complex creature. In network traffic terms, it captures all the headers of the IP packets running towards the network. From this, it filters out all known and legal traffic, including web traffic to the organization’s web server, mail traffic to and from its mail server, outgoing web traffic from company employees and DNS traffic to and from its DNS server.

There are other equally obvious advantages to using anomaly-based IDS. For example, because it detects any traffic that is new or unusual, the anomaly method is particularly good at identifying sweeps and probes towards network hardware. It can, therefore, give early warnings of potential intrusions, because probes and scans are the predecessors of all attacks. And this applies equally to any new service installed on any item of hardware – for example, Telnet deployed on a network router for maintenance purposes and forgotten about when the maintenance was finished. This makes anomaly-based IDS perfect for detecting anything from port anomalies and web anomalies to mis-formed attacks, where the URL is deliberately mis-typed.

CompTIA Security+ Question G-7

Peter, the Chief Technical Officer (CTO), is concerned about new malware being introduced into the corporate network. He has tasked the security engineers to implement a technology that is capable of alerting the team when unusual traffic is on the network. Which of the following types of technologies will BEST address this scenario?

A. Application Firewall
B. Anomaly Based IDS
C. Proxy Firewall
D. Signature IDS

Answer: B

Explanation:
Anomaly-based detection watches the ongoing activity in the environment and looks for abnormal occurrences. An anomaly-based monitoring or detection method relies on definitions of all valid forms of activity. This database of known valid activity allows the tool to detect any and all anomalies. Anomaly-based detection is commonly used for protocols. Because all the valid and legal forms of a protocol are known and can be defined, any variations from those known valid constructions are seen as anomalies.

CompTIA Security+ Question F-12

The network security engineer just deployed an IDS on the network, but the Chief Technical Officer (CTO) has concerns that the device is only able to detect known anomalies. Which of the following types of IDS has been deployed?

A. Signature Based IDS
B. Heuristic IDS
C. Behavior Based IDS
D. Anomaly Based IDS

Answer: A

Explanation:
A signature based IDS will monitor packets on the network and compare them against a database of signatures or attributes from known malicious threats.