6 Important Questions About Anomaly Detection

Violations of security policies within a computer or network are symbolic of the need for robust intrusion detection. From attackers accessing systems from the internet or authorized users conducting unauthorized activity internally, it seems that there are but few secure areas within IT systems.

There have been cutting-edge developments within cybersecurity that amass information and analyze events occurring in a system or network. The industry refers to these developments as intrusion detection

Intrusion detection is becoming more challenging owing to the expansion of heterogeneous computer systems and devices. Moreover, with the increasing connectivity of computer systems and networks in private and public companies, intruders have found relatively accessible opportunities. 

1) What is an intrusion detection system?

An intrusion detection system (IDS) is a hardware or software product that amasses and inspects information from various points within a computer or a network to catch attackers. This typically takes the form of monitoring the data flows or packets in a computer system or network. 

An IDS can find and provide real-time warnings of attempts to access unauthorized system resources by amassing and inspecting information. An IDS comes in many forms, from a host-based IDS to a network-based IDS. Typically, an IDS is placed inline at a spamming port, main switch or a virtual switch. 

Intrusion detection systems are classified as host-based IDS and network-based IDS.

2) Why is an IDS so valuable?

An IDS can act as a deterrent, averting untold damage to an IT system and beyond. An effective IDS can identify and extrude an attacker before the damage occurs. Even if an IDS does not wholly forestall an attacker, the quicker the intrusion is detected, an IDS can mitigate damage more quickly, and recovery is achieved. Since a considerable amount of information is collected during attempted intrusions, intrusion methods can, in effect, be learned, bolstering intrusion prevention methods. There are two approaches to intrusion detection: misuse detection and anomaly detection. Here, I will focus on anomaly detection. 

3) What is an anomaly intrusion detection system?

This type of IDS involves seeking out system or network activity that is abnormal from the usual or expected behavior of system entities and resources. Here, a behavior that is described as neither nominal nor normal is understood as 'anomalous'. Therefore, anomaly detection is vital in identifying activity that does not conform to an expected pattern. Examples here could be user login location, encrypted files, and sensitive file downloads over Microsoft 365.

Because of the 'normal' that it has learned based on activity patterns within observed data, whether that be within an on-premise network or on the cloud, this type of IDS is based on normal data sets or packets that can detect anomalies and monitor 'normal' data sets or packets. Artificial intelligence is typically used in this area, with vendors often using self-learning AI, meaning that it learns 'on the job', from the data and activity that it observes in situ. In effect, what we find is a type of intrusion system making millions or billions of probability-based calculations in light of evolving evidence.

4) How does an anomaly intrusion detection system work?

Typically, anomaly intrusion detection systems utilize self-organizing map (SOM) algorithms to essentially 'model' normal data to figure out whether a particular activity on a network or computer system is normal or abnormal. The SOM can use AI in this area, particularly unsupervised machine learning to map relationships – some often call this type of learning generating signatures to capture behavior – between input data. When data is processed, the intrusion detection system engenders a value to specify whether a behavior is normal or abnormal. 

5) What are the disadvantages of an anomaly intrusion detection system?

False positives often occur because the usual behavior of an intruder can overlap with the typical behavior of an authorized user. Moreover, false positives can occur when the system flags an error as a cyber threat. Therefore, events are flagged as malicious when they aren't. This can be problematic because the intrusion prevention system, next in line to remedy the "threat", can hinder IT operations. Additionally, a usual criticism is that cyber threat attackers aware of being monitored can simply train a computer system in such a way that their behavior is considered 'normal'. 

6) What are the advantages of an anomaly intrusion detection system?

An anomaly detection system can detect previously unknown attacks based on auditing activity. Thus, there are no predefined rules for intrusion detection. As many people highlight, signature or rule-based security systems can be a hazard insofar as they struggle with the unknown-unknowns. Additionally, an anomaly detection system can identify a threat before taking hold of a computer system and network, providing a crucial defense against cyber-attackers and safeguarding crucial business operations. 

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