Network Intrusion: How to Detect and Prevent It

Isabell Gaylord

A network intrusion refers to any forcible or unauthorized activity on a digital network. These unauthorized activities almost always imperil the security of networks and their data. Nowadays, online brands and companies are the usual subjects of these attacks. However, to properly deal with this, organizations should have a cybersecurity team in place. This will help organizations have an in-depth understanding of how these intrusions work and effect formidable detection and prevention systems.

Considering the number of activities like resume services taking place on digital networks, it has become increasingly difficult to identify irregularities that could indicate the occurrence of an intrusion. For instance, below is a rundown of popular attack techniques:

Attack Techniques

1. Multi-Routing

This method is also known as asymmetric routing. Indeed, the whole idea is to make use of more than one route to the targeted a network. As a result, this allows hackers to evade detection by having a very significant portion of questionable packets bypass intrusion sensors in some sections of the network. However, networks that are not configured for multi-routing are insusceptible to this technique.

2. Buffer Overflow Attacks

This method attempts to overwrite certain sections of computer memory within a network, replacing normal data in those memory locations with a string of commands that can later be used as part of the attack. However, this technique becomes more difficult to accomplish if the network designer installs boundary checking logic that identifies executable codes or lengthy and malicious URL strings before it can be written to the buffer.

3. Furtive Common Gateway Interface Scripts

The Common Gateway Interface (CGI) allows interaction between servers and clients on the web. Indeed, this serves as an easy opening for intruders to access hitherto secured network system files. However, where input verification or scan is not required for back-tracking, hackers can easily add the directory label “..” or the pipe “|” character to any file path name via covert CGI. Unfortunately, this allows them to access files that ordinarily shouldn’t be accessible via the web.

4. Protocol-Specific Attacks

Devices obey certain rules and procedures when performing network activities. These protocols such as IP, ICMP, ARP, and other various application protocols can leave loopholes for attacks. This can happen in the form of a protocol impersonation also known as spoofing. This technique gives hackers access to data they wouldn’t have access to otherwise or even crash targeted devices on a network.

5. Traffic Flooding

One other shrewd method of network intrusion is the creation of traffic loads that are too large for systems to properly screen. This would then induce chaos and congestion in the network environment. As a result, attackers have room to execute an undetected attack.

6. Trojan Horse Malware

These programs appear innocuous and do not replicate like a virus or a worm. However, they create a network backdoor that give attackers unfettered access to networks and any available data. Additionally, Trojan malware can attack networks from seemingly benign online repositories. This especially includes peer- to- peer file exchanges.

7. Worms

Worms are one of the easiest network intrusion systems, as well as one of the most damaging. In brief, a worm is a standalone computer virus that usually spread through email attachments or instant messaging. To this end, the virus ends up using large amounts of network resources and frustrating authorized activity. Some worms actively seek out specific types of confidential information such as financial information or any personal data relating to social security numbers. These attackers then communicate such data to intruders waiting outside the network. 

Intrusion Detection System (IDS)

Once organizations understand these attack techniques, their cybersecurity teams can then kick-start detection and prevention protocols.

An Intrustion Detection System (IDS) is a system that surveys a network for malicious activities and issues alert when it uncovers any such activity. Any threat is usually reported to the administrator. Additionally, this system consolidates outputs from multiple sources and filters malicious activities from false alarms.

Although intrusion detection systems monitor networks for suspicious or potentially malicious activity, they also look out for false alarms. This means that organizations need to adequately set up intrusion detection systems in order to recognize what regular traffic on the network looks like as compared to malicious activity. There are two types of Intrusion Detection System namely:

1. Network Intrusion Detection System (NIDS)

Network intrusion detection systems are placed at a strategic point within the network to examine traffic from all devices on the network. Primarily, it performs an analysis of passing traffic on the entire subnet and matches the traffic passed on the subnet to the collection of known attacks. Once it identifies an attack or senses abnormal behavior, it sends an alert to the administrator.

2. Host Intrusion Detection System (HIDS)

Host intrusion detection systems run on self-standing hosts or devices on the network. In short, it takes a snapshot of existing system files and matches it with the previous snapshots. Likewise, if the analytical system files were altered or deleted, it sends an alert to the administrator to investigate.

Detection Methods of IDS

1. Signature-Based Method

Signature-based IDS refers to the detection of attacks based on predefined criteria such as network traffic or identified malicious instruction sequences common to malware. The detected patterns are known as signatures. Signature-based IDS can easily detect already existent or known attack patterns while it’s difficult to detect new attacks with no existing patterns.

2. Anomaly-Based Method

Anomaly-based IDS were primarily introduced to detect unknown malware attacks which were, in part, due to rapid development of new malware. The whole idea is the use of machine learning to create a trustworthy activity model and compare new behavior against the model. It is then declared suspicious or potentially malicious if it is not found in the model.

It has a better-generalized property compared to the signature-based IDS because the models can be trained in accordance with the hardware configurations. Although the approach enables the detection of previously unknown attacks, it is susceptible to false positives that are previously unknown. Harmless and legitimate activity may also be classified as malicious.

Intrusion Prevention System (IPS)

Intrusion prevention systems are network security appliances that monitor network or system activities for malicious activity. Indeed, the main functions of the IPS are to identify malicious activity, gather information about this activity, report it and attempt to block it.

Intrusion Prevention Systems are considered as supplements to Intrusion Detection System because both IPS and IDS monitor network traffic and system activities for malicious activity. IPS can take proactive actions such as sending an alarm, resetting a connection or blocking traffic from the hostile IP address. There are four types of intrusion prevention system namely:

1. Network-Based Intrusion Prevention System

Firstly, Network Based Intrusion Prevention System primarily closely scans the whole network for irregular traffic through protocol analysis.

2. Wireless Intrusion Prevention System

More specifically, Wireless Intrusion Prevention System monitors wireless networks for suspicious activity by analyzing wireless networking protocols.

3. Network Behavior Analysis

Network Behavior Analysis carefully observes network traffic to identify threats that generate irregular traffic flows such as denial of service attacks, specific forms of malware and breach of policy.

4. Host-Based Intrusion Prevention System

Finally, Host-Based Intrusion Prevention Systems are an installed software package set up to monitor a single host for suspicious activity by analyzing activities occurring within the host.

Detection Methods of IPS

1. Signature-Based Detection

Firstly, signature-based IDS compares network packets with already-known attack patterns called signatures.

2. Statically Anomaly-Based Detection

Secondly, anomaly-based IDS operates network traffic and compares it against an established baseline. This baseline will identify what is normal for that network and what protocols are used. However, it may flag a safe activity as harmful if the baselines are not meticulously configured.

3. Stateful Protocol Analysis Detection

Finally, this IDS method recognizes deviations of protocols stated by comparing observed events with pre-configured profiles of generally accepted definitions of safe activities.


There are myriads of online brands and organizations including essay writers whose networks are susceptible to unwanted attacks and intrusion. It is therefore vital for these organizations to hire cybersecurity professionals who would be capable of surmounting these problems and delivering a hassle-free network.

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