Intrusion Prevention Software
Intrusion prevention software is considered an extension of Intrusion Detection Software as it typically uses the IDS data gathering to then enforce security parameters by dynamically changing firewall rules or putting other measures into place to prevent an intrusion. The main difference between an IDS and an IPS is that an IPS is placed inline in the network to be able to act upon the information and stop malicious activity.
Wikipedia provides us some great information about IPS:
Intrusion Prevention Systems can be classified into four different types:
Network-based Intrusion Prevention (NIPS): monitors the entire network for suspicious traffic by analyzing protocol activity.
Wireless Intrusion Prevention Systems (WIPS): monitors a wireless network for suspicious traffic by analyzing wireless networking protocols.
Network Behavior Analysis (NBA): examines network traffic to identify threats that generate unusual traffic flows, such as distributed denial of service (DDoS) attacks, certain forms of malware, and policy violations.
Host-based Intrusion Prevention (HIPS): an installed software package which monitors a single host for suspicious activity by analysing events occurring within that host.
The majority of intrusion prevention systems utilize one of three detection methods: signature-based, statistical anomaly-based, and stateful protocol analysis.
Signature-based Detection: This method of detection utilizes signatures, which are attack patterns that are preconfigured and predetermined. A signature-based intrusion prevention system monitors the network traffic for matches to these signatures. Once a match is found the intrusion prevention system takes the appropriate action. Signatures can be exploit-based or vulnerability-based. Exploit-based signatures analyze patterns appearing in exploits being protected against, while vulnerability-based signatures analyze vulnerabilities in a program, its execution, and conditions needed to exploit said vulnerability.
Statistical Anomaly-based Detection: This method of detection baselines performance of average network traffic conditions. After a baseline is created, the system intermittently samples network traffic, using statistical analysis to compare the sample to the set baseline. If the activity is outside the baseline parameters, the intrusion prevention system takes the appropriate action.
Stateful Protocol Analysis Detection: This method identifies deviations of protocol states by comparing observed events with “predetermined profiles of generally accepted definitions of benign activity.”
On the Network+ Exam
Like the IDS, the Network+ exam will test your knowledge of what an IPS is, why you would use one on the network, and the situations that an IPS will best be used in.