In this article by Warun Levesque, Michael McLafferty, and Arthur Salmon, the authors of the book Applied Network Security, we will be covering the following topics, which will give an introduction to network security:

• Murphy's law
• The definition of a hacker and the types
• The hacking process
• Recent events and statistics of network attacks
• Security for individual versus company
• Mitigation against threats
• Building an assessment

This world is changing rapidly with advancing network technologies. Unfortunately, sometimes the convenience of technology can outpace its security and safety. Technologies like the Internet of things is ushering in a new era of network communication. We also want to change the mindset of being in the field of network security. Most current cyber security professionals practice defensive and passive security. They mostly focus on mitigation and forensic tactics to analyze the aftermath of an attack. We want to change this mindset to one of Offensive security. This article will give insight on how a hacker thinks and what methods they use. Having knowledge of a hacker's tactics, will give the reader a great advantage in protecting any network from attack.

(For more resources related to this topic, see here.)

Murphy's law

Network security is much like Murphy's law in the sense that, if something can go wrong it will go wrong. To be successful at understanding and applying network security, a person must master the three Ps. The three Ps are, persistence, patience, and passion.

A cyber security professional must be persistent in their pursuit of a solution to a problem. Giving up is not an option. The answer will be there; it just may take more time than expected to find it. Having patience is also an important trait to master. When dealing with network anomalies, it is very easy to get frustrated. Taking a deep breath and keeping a cool head goes a long way in finding the correct solution to your network security problems. Finally, developing a passion for cyber security is critical to being a successful network security professional. Having that passion will drive you to learn more and evolve yourself on a daily basis to be better. Once you learn, then you will improve and perhaps go on to inspire others to reach similar aspirations in cyber security.

The definition of a hacker and the types

A hacker is a person who uses computers to gain unauthorized access to data. There are many different types of hackers. There are white hat, grey hat, and black hat hackers. Some hackers are defined for their intention. For example, a hacker that attacks for political reasons may be known as a hacktivist. A white hat hackers have no criminal intent, but instead focuses on finding and fixing network vulnerabilities.

Often companies will hire a white hat hacker to test the security of their network for vulnerabilities. A grey hat hacker is someone who may have criminal intent but not often for personal gain. Often a grey hat will seek to expose a network vulnerability without the permission from the owner of the network. A black hat hacker is purely criminal. They sole objective is personal gain. Black hat hackers take advantage of network vulnerabilities anyway they can for maximum benefit. A cyber-criminal is another type of black hat hacker, who is motivated to attack for illegal financial gain. A more basic type of hacker is known as a script kiddie. A script kiddie is a person who knows how to use basic hacking tools but doesn't understand how they work. They often lack the knowledge to launch any kind of real attack, but can still cause problems on a poorly protected network.

Hackers tools

There are a range of many different hacking tools. A tool like Nmap for example, is a great tool for both reconnaissance and scanning for network vulnerabilities. Some tools are grouped together to make toolkits and frameworks, such as the Social Engineering Toolkit and Metasploit framework.

The Metasploit framework is one of the most versatile and supported hacking tool frameworks available. Metasploit is built around a collection of highly effective modules, such as MSFvenom and provides access to an extensive database of exploits and vulnerabilities. There are also physical hacking tools. Devices like the Rubber Ducky and Wi-Fi Pineapple are good examples. The Rubber Ducky is a usb payload injector, that automatically injects a malicious virus into the device it's plugged into.

The Wi-Fi Pineapple can act as a rogue router and be used to launch man in the middle attacks. The Wi-Fi Pineapple also has a range of modules that allow it to execute multiple attack vectors. These types of tools are known as penetration testing equipment.

The hacking process

There are five main phases to the hacking process:

• Reconnaissance: The reconnaissance phase is often the most time consuming. This phase can last days, weeks, or even months sometimes depending on the target. The objective during the reconnaissance phase is to learn as much as possible about the potential target.
• Scanning: In this phase the hacker will scan for vulnerabilities in the network to exploit. These scans will look for weaknesses such as, open ports, open services, outdated applications (including operating systems), and the type of equipment being used on the network.
• Access: In this phase the hacker will use the knowledge gained in the previous phases to gain access to sensitive data or use the network to attack other targets. The objective of this phase is to have the attacker gain some level of control over other devices on the network.
• Maintaining access: During this phase a hacker will look at various options, such as creating a backdoor to maintain access to devices they have compromised. By creating a backdoor, a hacker can maintain a persistent attack on a network, without fear of losing access to the devices they have gained control over. Although when a backdoor is created, it increases the chance of a hacker being discovered. Backdoors are noisy and often leave a large footprint for IDS to follow.
• Covering your tracks: This phase is about hiding the intrusion of the network by the hacker as to not alert any IDS that may be monitoring the network. The objective of this phase is to erase any trace that an attack occurred on the network.

Recent events and statistics of network attacks

The news has been full of cyber-attacks in recent years. The number and scale of attacks are increasing at an alarming rate. It is important for anyone in network security to study these attacks. Staying current with this kind of information will help in defending your network from similar attacks.

Since 2015, the medical and insurance industry have been heavily targeted for cyber-attacks. On May 5th, 2015 Premera Blue Cross was attacked. This attack is said to have compromised at least 11 million customer accounts containing personal data. The attack exposed customer's names, birth dates, social security numbers, phone numbers, bank account information, mailing, and e-mail addresses. Another attack that was on a larger scale, was the attack on Anthem. It is estimated that 80 million personal data records were stolen from customers, employees, and even the Chief Executive Officer of Anthem. Another more infamous cyber-attack recently was the Sony hack. This hack was a little different than the Anthem and Blue Cross attacks, because it was carried out by hacktivist instead of cyber-criminals.

Even though both types of hacking are criminal, the fundamental reasoning and objectives of the attacks are quite different. The objective in the Sony attack was to disrupt and embarrass the executives at Sony as well as prevent a film from being released. No financial data was targeted. Instead the hackers went after personal e-mails of top executives. The hackers then released the e-mails to the public, causing humiliation to Sony and its executives. Many apologies were issued by Sony in the following weeks of the attack.

Large commercial retailers have also been a favorite target for hackers. An attack occurred against Home Depot in September 2014. That attack was on a large scale. It is estimated that over 56 million credit cards were compromised during the Home Depot attack. A similar attack but on a smaller scale was carried out against Staples in October 2014. During this attack, over 1.4 million credit card numbers were stolen. The statistics on cyber security attacks are eye opening.

It is estimated by some experts that cybercrime has a worldwide cost of 110 billion dollars a year. In a given year, over 15 million Americans will have their identified stolen through cyber-attacks, it is also estimated that 1.5 million people fall victim to cybercrime every day. These statistics are rapidly increasing and will continue to do so until more people take an active interest in network security.

Our defense

The baseline for preventing a potential security issues typically begins with hardening the security infrastructure, including firewalls, DMZ, and physical security platform. Entrusting only valid sources or individuals with personal data and or access to that data. That also includes being compliant with all regulations that apply to a given situation or business. Being aware of the types of breaches as well as your potential vulnerabilities. Also understanding is an individual or an organization a higher risk target for attacks. The question has to be asked, does one's organization promote security? This is done both at the personal and the business level to deter cyber-attacks?

After a decade of responding to incidents and helping customers recover from and increase their resilience against breaches. Organization may already have a security training and awareness (STA) program, or other training and program could have existed. As the security and threat landscape evolves organizations and individuals need to continually evaluate practices that are required and appropriate for the data they collect, transmit, retain, and destroy. Encryption of data at rest/in storage and in transit is a fundamental security requirement and the respective failure is frequently being cited as the cause for regulatory action and lawsuits. Enforce effective password management policies. Least privilege user access (LUA) is a core security strategy component, and all accounts should run with as few privileges and access levels as possible. Conduct regular security design and code reviews including penetration tests and vulnerability scans to identify and mitigate vulnerabilities. Require e-mail authentication on all inbound and outbound mail servers to help detect malicious e-mail including spear phishing and spoofed e-mail. Continuously monitor in real-time the security of your organization's infrastructure including collecting and analyzing all network traffic, and analyzing centralized logs (including firewall, IDS/IPS, VPN, and AV) using log management tools, as well as reviewing network statistics. Identify anomalous activity, investigate, and revise your view of anomalous activity accordingly. User training would be the biggest challenge, but is arguably the most important defense.

Security for individual versus company

One of the fundamental questions individuals need to ask themselves, is there a difference between them the individual and an organization? Individual security is less likely due to attack service area. However, there are tools and sites on the internet that can be utilized to detect and mitigate data breaches for both.https://haveibeenpwned.com/ or http://map.norsecorp.com/ are good sites to start with. The issue is that individuals believe they are not a target because there is little to gain from attacking individuals, but in truth everyone has the ability to become a target.

Wi-Fi vulnerabilities

Protecting wireless networks can be very challenging at times. There are many vulnerabilities that a hacker can exploit to compromise a wireless network. One of the basic Wi-Fi vulnerabilities is broadcasting the Service Set Identifier (SSID) of your wireless network. Broadcasting the SSID makes the wireless network easier to find and target.

Another vulnerability in Wi-Fi networks is using Media Access Control (MAC) addressesfor network authentication. A hacker can easily spoof or mimic a trusted MAC address to gain access to the network. Using weak encryption such as Wired Equivalent Privacy (WEP) will make your network an easy target for attack. There are many hacking tools available to crack any WEP key in under five minutes.

A major physical vulnerability in wireless networks are the Access Points (AP). Sometimes APs will be placed in poor locations that can be easily accessed by a hacker. A hacker may install what is called a rogue AP. This rogue AP will monitor the network for data that a hacker can use to escalate their attack.

Often this tactic is used to harvest the credentials of high ranking management personnel, to gain access to encrypted databases that contain the personal/financial data of employees and customers or both. Peer-to-peer technology can also be a vulnerability for wireless networks.

A hacker may gain access to a wireless network by using a legitimate user as an accepted entry point. Not using and enforcing security policies is also a major vulnerability found in wireless networks. Using security tools like Active Directory (deployed properly) will make it harder for a hacker to gain access to a network. Hackers will often go after low hanging fruit (easy targets), so having at least some deterrence will go a long way in protecting your wireless network.

Using Intrusion Detection Systems (IDS) in combination with Active Directory will immensely increase the defense of any wireless network. Although the most effective factor is, having a well-trained and informed cyber security professional watching over the network. The more a cyber security professional (threat hunter) understands the tactics of a hacker, the more effective that Threat hunter will become in discovering and neutralizing a network attack. Although there are many challenges in protecting a wireless network, with the proper planning and deployment those challenges can be overcome.

Knowns and unknowns

The toughest thing about an unknown risk to security is that they are unknown. Unless they are found they can stay hidden. A common practice to determine an unknown risk would be to identify all the known risks and attempt to mitigate them as best as possible. There are many sites available that can assist in this venture. The most helpful would be reports from CVE sites that identify vulnerabilities.

False positives

As it related to detection for an analyzed event there are four situations that exist in this context, corresponding to the relation between the result of the detection for an analyzed event. In this case, each of the corresponding situations mentioned in the preceding table are outlined as follows:

• True positive (TP): It is when the analyzed event is correctly classified as intrusion or as harmful/malicious.

  For example, a network security administrator enters their credentials into the Active Directory server and is granted administrator access.

• True negative (TN): It is when the analyzed event is correctly classified and correctly rejected.

  For example, an attacker uses a port like 4444 to communicate with a victim's device. An intrusion detection system detects network traffic on the authorized port and alerts the cyber security team to this potential malicious activity. The cyber security team quickly closes the port and isolates the infected device from the network.

• False positive (FP): It is when the analyzed event is innocuous or otherwise clean as it relates to perspective of security, however, the system classifies it as malicious or harmful.

  For example, a user types their password into a website's login text field. Instead of being granted access, the user is flagged for an SQL injection attempt by input sanitation. This is often caused when input sanitation is misconfigured.

• False negative (FN): It is when the analyzed event is malicious but it is classified as normal/innocuous.

  For example, an attacker inputs an SQL injection string into a text field found on a website to gain unauthorized access to database information. The website accepts the SQL injection as normal user behavior and grants access to the attacker. As it relates to detection, having systems correctly identify the given situations in paramount.

Mitigation against threats

There are many threats that a network faces. New network threats are emerging all the time. As a network security, professional, it would be wise to have a good understanding of effective mitigation techniques. For example, a hacker using a packet sniffer can be mitigated by only allowing the network admin to run a network analyzer (packet sniffer) on the network. A packet sniffer can usually detect another packet sniffer on the network right away.

Although, there are ways a knowledgeable hacker can disguise the packet sniffer as another piece of software. A hacker will not usually go to such lengths unless it is a highly-secured target. It is alarming that; most businesses do not properly monitor their network or even at all.

It is important for any business to have a business continuity/disaster recovery plan. This plan is intended to allow a business to continue to operate and recover from a serious network attack. The most common deployment of the continuity/disaster recovery plan is after a DDoS attack. A DDoS attack could potentially cost a business or organization millions of dollars is lost revenue and productivity. One of the most effective and hardest to mitigate attacks is social engineering.

All the most devastating network attacks have begun with some type of social engineering attack. One good example is the hack against Snapchat on February 26th, 2016. "Last Friday, Snapchat's payroll department was targeted by an isolated e-mail phishing scam in which a scammer impersonated our Chief Executive Officer and asked for employee payroll information," Snapchat explained in a blog post. Unfortunately, the phishing e-mail wasn't recognized for what it was — a scam — and payroll information about some current and former employees was disclosed externally. Socially engineered phishing e-mails, same as the one that affected Snapchat are common attack vectors for hackers.

The one difference between phishing e-mails from a few years ago, and the ones in 2016 is, the level of social engineering hackers are putting into the e-mails. The Snapchat HR phishing e-mail, indicated a high level of reconnaissance on the Chief Executive Officer of Snapchat. This reconnaissance most likely took months. This level of detail and targeting of an individual (Chief Executive Officer) is more accurately know as a spear-phishing e-mail. Spear-phishing campaigns go after one individual (fish) compared to phishing campaigns that are more general and may be sent to millions of users (fish). It is like casting a big open net into the water and seeing what comes back.

The only real way to mitigate against social engineering attacks is training and building awareness among users. By properly training the users that access the network, it will create a higher level of awareness against socially engineered attacks.

Building an assessment

Creating a network assessment is an important aspect of network security. A network assessment will allow for a better understanding of where vulnerabilities may be found within the network. It is important to know precisely what you are doing during a network assessment. If the assessment is done wrong, you could cause great harm to the network you are trying to protect.

Before you start the network assessment, you should determine the objectives of the assessment itself. Are you trying to identify if the network has any open ports that shouldn't be? Is your objective to quantify how much traffic flows through the network at any given time or a specific time?

Once you decide on the objectives of the network assessment, you will then be able to choose the type of tools you will use. Network assessment tools are often known as penetration testing tools. A person who employs these tools is known as a penetration tester or pen tester.

These tools are designed to find and exploit network vulnerabilities, so that they can be fixed before a real attack occurs. That is why it is important to know what you are doing when using penetration testing tools during an assessment.

Sometimes network assessments require a team. It is important to have an accurate idea of the scale of the network before you pick your team. In a large enterprise network, it can be easy to become overwhelmed by tasks to complete without enough support. Once the scale of the network assessment is complete, the next step would be to ensure you have written permission and scope from management. All parties involved in the network assessment must be clear on what can and cannot be done to the network during the assessment.

After the assessment is completed, the last step is creating a report to educate concerned parties of the findings. Providing detailed information and solutions to vulnerabilities will help keep the network up to date on defense. The report will also be able to determine if there are any viruses lying dormant, waiting for the opportune time to attack the network. Network assessments should be conducted routinely and frequently to help ensure strong networksecurity.

Summary

In this article we covered the fundamentals of network security. It began by explaining the importance of having network security and what should be done to secure the network. It also covered the different ways physical security can be applied. The importance of having security policies in place and wireless security was discussed. This article also spoke about wireless security policies and why they are important.

Resources for Article:

Further resources on this subject:

• API and Intent-Driven Networking [article]
• Deploying First Server [article]
• Point-to-Point Networks [article]