What is the Most Important Functionality of a Firewall?Every large corporate network today, should have at least one firewall. The purpose of the firewall is to enable the existing network to automatically avoid being connected to a particular network which may otherwise be malicious or have other problems. It is used to keep threats away from the corporate network. The most important functionality of a firewall is to detect connections that belong to another application and that it can use. Based on this, the firewall is in charge of blocking, redirecting or accepting the traffic. In Linux, the firewall is often known as iptables, syslinux or autofs. iptables is the default firewall built in the upstream Linux kernel. You can use syslinux, or you can build your own firewall in place. One of the major factors that increase the amount of data traffic is also the impact of the internet, websites, blogging etc. which now allow people to publish their work on the net for a wide audience. Many people also make use of the net for internet shopping, online gaming and shopping etc. This implies a lot of traffic which becomes a real security riskThe need for a firewall is no longer a question of security for the average network but also when network usage is immense and very much out of the norm, to keep things in order. The most essential function of a firewall is to block the traffic that has an identifying characteristic of malicious or criminal activity. They also do this by detecting the source of the malicious network traffic. The unique characteristic may be known as MAC address or TCP port or even UDP port number. The special character in a word is the port number. The combination of a man-in-the-middle attack, a worm or other malicious software that could intercept and control or even make permanent changes to your network traffic. By using a firewall, it prevents the same port from being exploited to carry out these malicious activities. Stop Unnecessary TrafficMany people often complain of their firewall and other network tools logging traffic. The question then is why is it logging the traffic? Why not stop the unnecessary traffic first? This is because the analysis of the incoming traffic allows you to determine the type of application, the type of operating system and the operating system version. Proper analysis will enable you to know how you should handle the system. Thus, it is necessary to stop the potentially malicious traffic to avoid a breach of security. The Make no Mistake! What is the primary function of a firewall is to secure the network. The number of incoming connections should be monitored to determine the threat before you do any compromise with the network. The moment a threat is identified, it must be immediately stopped and the traffic contained. Do not wait until an attack or breach happens before you act. This would allow an attacker to see how you manage your network. Assess and ImproveHowever, the best way to determine how effective the firewall is is to look at its performance. When you are moving to a new network, it is always advisable to install a new firewall on it. If the firewall is functioning efficiently, then you can go ahead and change the location of the firewall. If there are issues with it, you may need to change it. The reason is simple – the strength of the firewall lies with its performance. So, by examining its performance, you can determine the status of it. If there are a lot of errors and by not blocking out legitimate traffic, then you will need to improve its performance. Often times, you can get this done with the help of a firewall pro. When you are looking at the available firewall tools, you should examine and test to see which ones you find satisfactory and which you can recommend to your network. Cyber Security Technology and TechniquesFirewalls are used to secure your networks. Firewalls prevent malicious attacks by controlling access to the network. Who has access to the network?If your firewall prevents clients from connecting to a specific host, then it prevents clients from connecting to an organisation’s data or resources that are not supposed to be accessible to them. How do I get a firewall?You can buy a firewall by yourself or get a vendor to make a custom solution for you. You can read more about the advantage of buying your firewall made by the vendor versus buying it yourself. Why a firewall?Firewalls separate networks by using rules. How can I monitor my firewall?To monitor your firewall, you can login to the web interface from a trusted IP address to monitor it. It is useful for people that don’t know how to use the firewall and for security professionals. How can I configure my firewall?When setting up a firewall, there are several different options. One is to use a setup utility to perform the configuration; the other option is to edit configuration files directly. This prevents your primary firewall from leaking data about your cloud hosts or public cloud hosts. This ensures that the primary firewall doesn’t accidentally connect to the wrong host. When should I replace my firewall?When your firewall stops working; that means that it’s time to replace the device. Some of them are easier to install than others. To get around this, make sure that all ports are closed in your firewall and don’t enable any of the firewall settings. In the past decade, we’ve seen a huge evolution in how firewall protects networks. However, nowadays, there are more important things to consider: Malware is the number one cause of intrusion on networks today. Trends in the cyber-sphereLet’s be honest, there’s a good chance that you or your company is being targeted by an advanced attacker today. The good news is that, from the sounds of it, some of these advanced attacks are getting less advanced every year. As an example, even ransomware (in which you make a ransom payment in order to regain access to your files) is becoming less and less popular every day. However, this type of advanced attack is still very threatening, and businesses still need to be prepared. So, what do we need to do to protect our networks from attackers?Whenever you think about the bad guys, you think about complex networks and elaborate malware. You may not have thought about your infrastructure. As you can see, it’s probably a good idea to start by developing a healthy security habit and protection for your infrastructure. Is it your email, your virtual private network, your website, a cryptocurrency exchange, a chat platform, a social media platform? Is there a high volume of users? This is often known as multifactor authentication. In order to be able to make a log out request, you will first need to enter a password, which will then be verified with a one-time password sent via SMS or generated by a physical security token, such as a USB Flash drive or a mobile phone. Is there any way to protect your systems and data?The good news is that some of the above threats are evolving and becoming less complex. However, you’ll still need to protect your systems. And sometimes, even the simplest solutions can go a long way. According to Gartner, the frequency of cyberattacks may have decreased. However, the severity of these attacks is rising. Steps to avoid data breachesHow can we know if our systems are as safe as we need them to be? How do we ensure our systems are as protected as we should be? Here are some of the steps you can take: They may also be able to help you identify a new security partner that is best for your business needs. This is a good training exercise for them. Cloud-based servicesIt’s all about the cloud. Whether your business is based in the cloud, or you operate in a hybrid, many of your staff should use cloud-based services. We use different cloud storage services: AWS, Microsoft Azure and Google Cloud. Everything is stored in the cloud. The benefits are many. Using the cloud, you don’t need to worry about hardware maintenance, updates, or replacements. For example, when working remotely, employees can access their documents and work seamlessly. You can also integrate your apps to your cloud services. This is a great way for employees to access information anywhere on any device. Cloud computing also reduces your IT complexityYou don’t need to buy all the computers, servers and storage you need to operate the business. You can work with a few cloud services instead of buying them all. This has important implications because when a breach occurs, the first thing people will do is look for their information. While most cloud storage services have security in place, you still need to ensure your system is fully protected from viruses and malware. Use redundancyTo increase your data protection, you can work with different cloud storage services. This gives you the flexibility to move files back and forth. You can keep the data on your premises or you can move it to the cloud. There is also a slight performance increase, which is a good thing. The benefits of the cloud can be highly beneficial for your business. There are many tools available to help you monitor your network and security. The resources available are really useful. You need to pay attention to what these tools provide to you because they can help you protect your company from cyber threats. Reduce IT complexityEnterprise security can be overwhelming. The network systems need to be properly configured. It is also important that you have a team to maintain the network and IT security. Having a trained team and also having the proper tools to do the job is important. Don’t use old hardwareAccording to Cisco, 60% of security incidents have occurred using outdated tools or technologies. So, while your network is out of date, your IT system is also too. A secure, reliable and secure network that is built on modern technology is what your business needs. This can help you make use of the cloud to help improve your business productivity. You can ensure your company’s security by using firewalls, and encryption to store your data. It is very important that you have this kind of system installed to stop potential security threats. With the cloud you don’t need to worry about things like data leaks. You can store everything in the cloud. They have great customer support that can help you save time and money. Using the cloud, you don’t need to worry about hardware maintenance and repairs, nor about updating the software. You can easily recover your data from the cloud when there is an incident. You can also use the cloud for your backups. If your computer goes down, the data is safe. This is important for protecting your data from malicious attacks. With cloud, you can store your data on shared or private cloud services. Your business can benefit from improved efficiency, faster access to the data and more security. Firewall key strengthNo doubts, the most important functionality of a firewall is to protect the system from attacks coming from the network. So, by getting access to these attack vectors, the adversary can try to achieve various goals by gaining remote access or by modifying the internal information. That is a famous saying of Dan Brown, the author of the best selling novel, The Da Vinci Code. The author of the book states that information security and strong authentication will hinder the success of an adversary by providing key sources for information on the target system that is to be used as part of a deception. To get access to the compromised system, an attacker needs to understand the limitations of an existing solution and how it can be attacked. Since the system is hard to discover and almost impossible to hack, the attack can be conducted for long periods without being noticed. However, there is one main principle that is the same for all the configuration tools. Security By ObscurityIn a nutshell, this principle means to restrict access to critical system functions by the network attackers. The attacker will not be able to perform his desired actions in a secure network. For example, the attacker who wants to do something harmful to the network will not be able to do so, if he can’t find out the specific port to connect to. In fact, the firewall shouldn’t allow connection to certain external ports. This way, the system will be more secure by providing protection against external attacks and man-in-the-middle attacks. However, complexity should not be the enemy of security. In fact, the more complex the firewall, the more secure it is. Also, the more features a firewall has, the harder it is to maintain. It will be harder for the administrators to understand all the configurable options. This may lead to a scenario where no options are supported and all users may not have access to the settings. For example, it has a variety of features such as User-Agent, Client-Application, port-based, HTTP-based, TCP/UDP-based, and even NNTP based. And if we are to build a multi-layered architecture, we can have many such security systems. The firewall itself acts as the middle layer. On the other side, we have another layer that must interface with other security systems, such as the System, our RAID array, NFS, etc. A complex architecture makes it easy to manage and integrate. Why multilayer architecture?Multilayer architecture is good because each layer should be as secure as possible, and each layer should also be as simple as possible. This way, if you implement a security solution for your environment, you should not worry about how to protect your firewall, because you don’t have to. If you integrate a security solution, you should worry about how to maintain it. When designing your firewall, the goal is to combine as many features as possible with fewest number of settings. When designing your firewall, the goal is to combine as many features as possible with fewest number of settings. We could define a multi-layer architecture that integrates with everything, even when an enterprise is configured with a single NAS. For example, let’s say the SMTP server is managed with one host, and users have to configure SMTP on their own. We could use a self-service portal that can control the SMTP server on our firewall, while also managing it. The user could configure and manage all his devices on the firewall without a problem. This is why we use the term “multi-layered architecture”. We are talking about multi-layer architecture. If you use a self-service portal, you can easily manage your security solutions.) The management system can focus on its core responsibilities, such as managing servers and services, while the firewall focuses on security. This allows us to keep the management system simple and lightweight, while giving security systems enough room to breathe. If you look at the architecture of the firewall running at a major city ISP, you may have noticed that you have a different configuration than a tier 1 ISP. The tier 1 is running the NTP infrastructure, and the tier 2 is running the DNS servers. They are both connecting to the same public IP address, which is the public IP address for the physical layer, the first IP layer in the network. This public IP address is normally associated with an DHCP server. You may also notice that when you have more than four network zones configured, they would all be specified on this same public IP address. The public IP address is normally set to 10.0.0.0, and it is commonly referred to as 172.16.0.x. What happens when I open up the box to connect my network into the box? The first thing I have to do is to activate the firewall for the first zone. This has to be done by simply editing the configuration file, or if I use Windows, I can just right-click on the Network tab of my file manager and I can just select Network > Enable firewall. Once this first zone has been activated, it has a default IP address of 10.0.0.1. At a tier 2 ISP, you would normally have this router and its associated DHCP server at 10.0.2.1. If you were routing traffic to a local DNS server on a public IP address, you would route it to the Tier 1's IP address of 172.16.0.x. So for me to just connect into my tier 2 ISP network without configuring any sort of firewall, I would have to have an active or modified firewall for every single network zone that I wanted to connect into. In order to accomplish this, you would have to configure a router in the first network zone that would accept all of the traffic from any other network zones on your network. If you go back to the architecture of a tier 1 ISP, the router would usually be configured to accept packets that originate on the network of tier 1, and it would forward these packets onto the network of tier 2. You may also notice that the same router is responsible for being the DHCP server of the network, and when you have multiple DHCP servers, the traffic to each one of them is forwarded onto the network of tier 1. Can a Firewall Stop All Attacks?If your answer is that it stops all network attacks, you're not alone. But a firewall that simply blocks the "WannaCry worm" (aka WannaCrypt) isn't likely to be all that effective.
One common method of detection is a binary scan, where the firewall checks for any connections that are not allowed by a specified ruleset. A good firewall is also important for defending against accidental access, keeping unapproved devices from malicious actors, and doing proper infrastructure monitoring. In this article we're going to look at what a good firewall does, and how to tell when one isn't behaving properly. Modern networks are heterogeneous, composed of physical devices, applications, and services that may be connected to the internet through Ethernet, IPv4, IPv6, IPSec, SMTP, and HTTP. An effective cybersecurity strategy requires protection against vulnerabilities of all types, for all connections to the internet. Read More Why Do Firewalls Work?Almost all network attacks try to hide their malicious behavior behind other protocols. The WannaCrypt malware uses the C2 protocol, and DNS is the protocol that it uses to connect to the command and control servers. DNS tries to match the domain name requested by the client against a list of possible DNS records. But the DNS record is stored only in the memory of the computer at the time the request is made, and the requests are sent out simultaneously over the internet. Your firewall will either try to force those connections through, or it won't allow them through. This behavior is known as DNS cache poisoning, and some firewalls will prevent users from making such requests because it gives an attacker an easy way to bypass all of the data filters that are typically built into firewalls. Once the server acknowledged receipt of the packet, it didn't need to accept another packet for a similar attack to succeed. When this happens, the firewall will allow the traffic to pass through. As part of a botnet, a DNS server could be used to perform brute force attacks against other servers, making the DNS request from the victim just another piece of data to be sent over the network. Lack of Response from A DNS ServerIn a recent DNS flaw, malware writers were able to bypass firewalls by using a web server to perform a man-in-the-middle attack on a DNS server. The DNS server, in turn, would pretend to respond to the request from the browser, allowing the malware to extract information about the victim. The lack of any response from the DNS server allowed the malware to continue the attack. So it doesn't matter how much time and energy a firewall devotes to filtering DNS traffic, if there's no response from the DNS server, it won't help. The Whois lookup table includes the names of the person or company who owns the domain. If the owner's name is listed, the DNS server can see that the request is legitimate. If the owner's name is not listed, the DNS server can see that the request is invalid, but it does not appear in the Whois lookup table, so it is not seen by the firewall. It's not as easy as blocking every DNS request from an attacker's IP address, and that will protect you only if the attacker is malicious, in which case the firewall should block everything. In the case of WannaCry, it's not clear that the attackers were malicious, so you probably don't need to filter DNS requests, but you should make sure that the DNS server you're using is not part of a botnet or compromised system. What If I Have Multiple Firewalls?You probably have a lot of firewalls. Fortunately, as long as they're all updated with the latest patches, there's not much of a problem. As long as the C2 server is blocked on each firewall, there's not much you can do. However, you should remember that the same threat could be delivered to each firewall in your network. So you shouldn't necessarily just connect to the Internet using only the firewall that is recognized as the main gateway. The other firewalls on your network should be checked to make sure they are all up to date. You might also have an antivirus system, a spam filter, and so on. So you might have a number of different systems for spotting attacks. This is an important part of a layered approach to security, because you never know where an attack will come from, and you never know when an attack will actually succeed. If all of these systems are working, you can reduce your attack surface. How Do I Know When One of My Firewalls Could Be Interrupting My Network?This is the part where a lot of people get worried, because they're not sure whether it's better to let one firewall go into an all-out attack mode and let the other systems catch up to that one, or whether it's better to stop one firewall in case it isn't up to date and is shutting down the whole network. If the firewall that is holding up your network has been going on for more than a few seconds, then it's time to stop it. If your firewall is taking too long to respond, then you probably need to stop it. However, you'll have to wait a bit before you can fully restart a firewall that isn't responding. A firewall that has been using all its CPU power to answer all of the requests and have no other idle time can take a while to respond. In that case, you need to stop it. However, as long as the firewall isn't doing anything illegal, or causing any problems to your network or other devices, you can wait a bit before you restart it. You could also wait until the firewalls you want to use are rebooted, if they need it. How Do I Know That I'm Safe?You can tell if you're safe from DNS cache poisoning by checking the DNS server logs to see when the attack took place. You should watch the logs for a few minutes to see how long it took for each DNS server to return an answer. In the case of WannaCry, it took a while for the DNS server to return an answer, so it was a little over three minutes before the systems all returned to normal. The important thing is that the DNS servers were offline, which means that they weren't in the Whois lookup table, and so were not yet affected by the attacks. You'll probably get an answer that includes the WHOIS domain name. Check to make sure that your DNS cache isn't corrupted, and then try to access the DNS information again. If you have access to the DNS servers that you're not using, then you can run the same test using the other servers in the list. This can be done in your web browser. If your browser doesn't support it, then there are other means. You can block access to any HTTP server that you don't trust, or you can try to block all HTTPS servers. If you're not sure which of these methods you want to use, then you should probably check your firewall logs to see if there is anything there that suggests that HTTP or HTTPS connections are becoming corrupted. |