Your firewall is the first line of defense between your network and oblivion. Depending on how you’ve configured it, it can be a lifesaver in many severe situations. But a firewall alone might not be enough. This is why having an intrusion prevention system (IPS) in place is a fantastic idea. It’s never a bad idea to invest in something that boosts your overall cybersecurity.
In this article, I’ll go through what an intrusion prevention system is, why you need one, and how they work. As always, let’s go ahead and start with that definition!
What Is an Intrusion Prevention System?
An intrusion prevention system is typically a hardware or software solution that monitors network activity for malicious activity and takes action to stop them. Specifically, it can help you assess network traffic and filter out malicious data packets. You’d find an IPS hosted just after your main firewall. While a firewall can inspect packet headers and footers, an IPS can inspect packet data. This combination results in a robust cybersecurity duo. Today, you can find IPS solutions integrated into next-generation firewalls (NGFWs).
While firewalls can help you in perimeter defense, you can deploy multiple IPS solutions as part of your unified threat management solution inside your network. The more IPS solutions you have in your network, the less likely you’ll be the victim of a cyberattack. That said, some of the main downsides include cost and slower traffic in the long run, so keep that in mind.
Alright, now you know the “what”. But what about the “why”?
Why You Need an Intrusion Prevention System
Although firewalls are necessary, they aren’t always enough to protect against cyberattacks.
For starters, they don’t help you spot all threats because they only inspect packet headers and footers, not content. They also work on known threats and rules you assign, so they may not be all-inclusive. And when assessing your network security, you must look into where you or a user made a mistake.
So, you’ll need something to detect and mop up threats that pass through a firewall. An intrusion prevention system is your solution. In short, it’s the perfect companion for any firewall.
All good so far? Great, now it’s time to get into the “how”!
How Does an Intrusion Prevention System Work?
The inner workings of an IPS depend on several detection methods. During your search for the best IPS for your business, you’ll find 3 different threat detection methods. Vendors often bundle one or more of these detection methods in their solutions. More methods result in better threat detection overall.
Knowing how each method works is paramount when searching for the right solution for your business. The methods used can also affect how you implement your IPS in your business. That said, let’s dive into these methods, starting with signature-based detection.
1. Signature-Based Detection
Signature-based solutions inspect packets in your network and compare them with attack patterns known as signatures. This method assesses anomalies by comparing system data to the features of known attack attributes.
To be clear, advanced threats often use the precursory building blocks of conventional and known malware, like trojans and worms, to create a targeted attack. These advanced threats are much more likely to have a high success rate in most cases.
But they also have their weaknesses. For instance, some of these threats open a backdoor which results in them leaving a comms signature behind. Traditional firewalls can’t detect these signatures normally, while a solution specializing in signature detection can!
2. Stateful Protocol Analysis Detection
Stateful protocol analysis detection recognizes any divergence from a defined protocol. The protocol here is the rule used to define and constrain traffic.
For instance, if a user wants to connect to a web server outside your network, you can create a rule to enable the same server IP to return to the network on the same port data. This won’t work if the user’s query returns from a different IP or to a different port. The protocols themselves can be time-dependent or as complex as the solution you use allows.
The protocols or rules used to define the correct state for traffic are a great way to ensure bad actors aren’t intercepting or redirecting your traffic. Time-limited traffic can also help protect you from credential replay attacks. This happens because old transmissions automatically get rejected based on the protocol definitions and rules they use.
Another example revolves around Secure File Transfer Protocol (SFTP) data transfers. Here, a connection needs to be in an authenticated state for data transfer to occur. If no authentication is present, the data transfer won’t work.
Overall, your SMB can benefit from a stateful protocol analysis detection method if you want to secure web, email, and user communications.
3. Statistical Anomaly-Based Detection
Statistical anomaly-based solutions monitor network traffic metrics and compare them against an established baseline. The baseline will identify what’s typical for that network by comparing the data sent along with the protocols used.
To clarify, the baseline your IPS creates uses historical data from regular traffic on your network. As your business grows and the traffic increases, the baseline changes, like a running average. The solution can also calculate standard deviation values from the nominal variation. These values help define your network’s nominal operating limits for a given metric. You can then use these values to determine if a specific value is suspicious or within normal network usage.
As you can see, this method is very accurate and can help reduce false positives depending on the number of metrics used. Likewise, you can use this method in combination with the other 2 methods to improve threat-hunting practices. If you’re a larger company, you can even use this method along with extended detection and response (XDR) tools to feed accurate threat detection to your security operations center (SOC).
Now that you know the 3 different detection methods an IPS uses, let’s take a look at 4 must-have features your new IPS should have!
Top 4 Must-Have IPS Features
It’s a great idea to clearly understand the features your solution should have before making a decision. Here, you’ll learn more about the top features any self-respecting IPS should have, so let’s dive in.
1. Information Gathering
Your intrusion prevention system solution must be able to identify hosts, operating systems, and applications your company uses. You’ll need this feature to help identify your network and where you’re relaying your traffic. This information is critical for threat detection, understanding threat objectives, and remediation purposes. The better your IPS is at gathering this information, the more metrics it can monitor. As a result, you’ll have increased threat detection and decreased false positives.
2. Event Logging
Your IPS should log network traffic data needed to detect and manage cyberthreats. This data can confirm threat validity, help investigate incidents, and check events between the solution and other logging sources on your network.
You must also remember to check the logs created to meet your security needs and provide a convenient log management solution. Ideally, the IPS solution will integrate logging capability and handle everything from one console. To this end, look for fully integrated cybersecurity solutions from one vendor.
Your IPS should also allow you to store logs locally and send copies of logs to centralized logging servers. Additionally, check for a clock synchronization feature. Most solutions will offer Network Time Protocol (NTP) to achieve this. It can be annoying having to look at logs with different time stamps to try and figure out what’s happening in your network!
3. Threat Detection
IPS solutions need to offer as many detection capabilities as possible. The types of events detected and detection accuracy can vary greatly on these capabilities. Additionally, most solutions require some degree of historical data and fine-tuning to work effectively. You’ll often find that the better the IPS, the less time it takes to establish a credible network profile to assess threats. So you should look for a solution that has an automatic setup process.
4. Threat Prevention
In addition to threat detection capabilities, your IPS must offer multiple prevention options to help deal with threats. Although these options will vary greatly for each solution, you should have some way to specify the prevention method used for your IT admins. For instance, when it comes to state-based disparities, will you receive an email or push notification? Remember to keep this in mind when on the hunt for a good solution.
Now then, how about some tips on deploying an intrusion prevention system?
Tips on Deploying an Intrusion Prevention System
Adding an IPS solution to your network is straightforward in most cases. That said, below are a few tips to help you.
First things first, before you even start planning, you need to remember that cybersecurity needs evolve as the business grows. IPS integration is one of the first cybersecurity measures you add to a network, along with a firewall and antivirus. As your business grows, the IPS needs to scale quickly along with other cybersecurity measures and integrate with more streamlined unified threat management approaches.
When your business becomes more prominent, and your system gets too complex to manage, you should think of adding a SOC. SOC team members highly value accurate threat detection. To this end, you need to integrate your IPS, IDS, and other security measures, often with an XDR tool. This combo helps reduce false positives and streamline workflows for cybersecurity teams to remediate potential hazards.
Knowing how your cybersecurity grows enables you to futureproof your cybersecurity solution and reduce redundant purchases. To this end, plan to use an IPS that can scale; for many, this is through a subscription-based service. Also, consider a vendor-based cloud-hosted solution, as this can reduce on-site infrastructure CAPEX requirements in the long run.
Modern IPS solutions will use an administrator’s intent through an abstraction layer to install and configure IPS solutions. Search for solutions that do this. But if you can’t find one that meets your needs, here are a few more critical details you need to know when adding an IPS to your network.
If you have a switched network, consider using port mirroring to monitor traffic on the VLAN. Cisco coined Switch Port Analyzer (SPAN) to describe this form of monitoring. The drawback of SPAN is the need to double the amount of data sent across your network. To do that, you can use the following configuration:
- Network: Public
- Port type: SPAN
- Source: Router switch port
- Traffic: Both
On the other hand, you can use a Remote SPAN (RSPAN) for multiple switch environments to copy monitoring frames across your network. To do this, you can use a configuration much like the one below:
- Network: Public
- Port type: RSPAN
- Source: Public Network VLAN
- Traffic: Both
Overall, using this configuration enables you to detect internal and external threats against any host in your network. That said, expect more overheads on switches and the need to scale infrastructure to meet demand as your business grows. But you can still switch back to a SPAN configuration.
An IPS solution is network and disk I/O intensive. Specifically, network monitoring is the system’s most intensive aspect. Due to this, you should seek cloud-based security solutions. These solutions improve performance overall. Having an on-prem solution using your existing infrastructure can hinder performance. A cloud-based solution is highly recommended in this case.
If your IPS detects and blocks a threat, bad actors will know what stopped their malware. This is because the rejection notification will come from the IPS solution. In a sense, this helps provide more information about your network to the bad actor. To reduce this risk, you should encrypt all your notifications. And this boosts your system integrity.
Time for a recap!
You now know everything you need to know about IPS integration into your business. As you’ve read, an intrusion prevention system is vital to combine with your other cybersecurity tools. You can integrate IPS solutions into hardware or software-based products. Furthermore, you can host them either on-site or in the cloud. To make your life easier, you should go with a cloud-based solution. This type of solution scales better and reduces CAPEX requirements.
When selecting a solution, use one designed to integrate into other offerings by the same vendor and check they can all scale and service a SOC. Doing so will effectively futureproof your cybersecurity scaling capabilities and reduce overall lifetime costs to the business.
Do you have more questions about intrusion prevention systems? Check out the FAQ and Resources sections below!
What differentiates intrusion prevention systems (IPS) from intrusion detection systems (IDS)?
An IPS can stop threats, while an IDS can only alert admins of a threat. Analysts can interpret the log data found in logs created by IDS alerts. This is often useful for more advanced threats as you can assess the bad actor’s strategy and goal. An IPS solution is far better at automatically handling less advanced threats.
Does an IPS solution reduce traffic speed?
Yes, an intrusion prevention system can reduce network speed as it assesses packet headers and contents. That said, you’ll find that most users never notice the compromise in speed. To this end, you should still consider using IPS solutions to protect your network just in case a bad actor slips by your firewall.
Where can I add an IPS?
You can add one practically anywhere on your network. For strategic efficiency, locations often include immediately after your main router’s firewall, switches, and internal network routers. You can also add an IPS at silo gateways or segmented parts in your network. Overall, they’re a staple for improving business IPsec.
Do next-generation firewalls (NGFWs) integrate IPS solutions?
Yes, NGFWs have features often previously reserved for IPS solutions. This is great for businesses that often think that IPS solutions are only useful for more extensive networks, which is false. NGFWs also include other features like using admin intent to help install and configure intelligent algorithms to reduce human errors.
Is having one IPS solution good enough to protect my business?
You can often find IPS solutions at several network segments such as gateways, switches, and routers. If you can only add one solution, ensure it’s immediately behind your main ingress-egress router. This will help monitor and track traffic data going in or out of your network.
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