What is Cloud Intrusion Detection?

In nearly all cybersecurity plans, intrusion detection is a critical component. After all, if you don’t know when you’ve been breached, you can’t contain it. But, as the technical world has continued to collectively embrace the cloud, the complexities of intrusion detection have increased. Now, you’re not simply protecting assets in your own facility, you’re protecting them in facilities you have little to no control over, which can require more nuanced planning and collaboration between all of the various moving parts.

How Intrusion Detection in the Cloud works

At a high level, cloud intrusion detection works much the same as on-premises intrusion detection – by monitoring system activity and analyzing patterns to identify malicious activity. A well-architected intrusion detection system can detect anomalous behavior and alert administrators when suspicious activity is detected. The more aware of your infrastructure an intrusion detection system is, the more effective it is.

For example, being aware of the relative physical location and time of users as they authenticate might be a useful parameter that an intrusion detection system could take into account. By identifying and understanding the login patterns of the users of the system, outliers can be flagged for review. So, if a user authenticates at an unusual time of day or from an unusual IP address, then a well-defined intrusion detection system can log those instances and alert administrators to a potential breach.

Benefits of using Intrusion Detection in the Cloud

The most obvious benefit of cloud intrusion detection systems is how they can improve an organization’s security posture by identifying and helping contain potential malicious activity in a timely manner. But while it might be obvious that cloud intrusion detection can help improve the overall security of any cloud-native organization, there are other specific benefits that are important to call out. From increased visibility into system activity to faster response times and even more focused alerting, intrusion detection is an excellent way to ensure resources are invested where they are needed.

Increased visibility

The key word in “intrusion detection” is “detection.” While the value of cloud intrusion detection systems is that they can alert administrators to suspicious activity quickly, those alerts are ultimately powered by observability data about the entire underlying system. From network traffic monitoring to system and user activity or even access logs and behavioral analysis, this data provides a more complete picture of what is happening within the cloud-based infrastructure an organization relies on. With greater visibility into all of this system activity, organizations are better equipped to identify and address malicious behaviors quickly and efficiently.

Faster response time

Just as smoke alarms allow you to respond more quickly to a potential fire than simply waiting for the smoke to reach your nose, cloud intrusion detection systems allow you to respond more quickly to potential breaches and malicious activity long before it’s noticed by end-users and other stakeholders. By providing real-time alerts, intrusion detection systems give you the ability to address problems as they happen rather than after the damage has already been done. Additionally, many cloud intrusion detection systems can also be configured to automatically take action when suspicious activity is detected, rather than alerting and waiting for human intervention, which further reduces response times.

Focused alerting

One of the most valuable aspects of cloud intrusion detection systems is the fact that alerts are focused. By identifying probable breaches, administrators can be alerted to critical and timely incidents rather than dealing with notification fatigue due to unspecific alerts. By leveraging techniques like machine learning to analyze system activity and identify patterns, many intrusion detection systems are better able to identify and alert administrators of malicious activity without generating false positives. This allows administrators to focus their attention on the most important alerts and respond quickly to what matters.

Flavors of Cloud Intrusion Detection

While this article has thus far been focused on relatively general cloud intrusion detection systems, there are actually several methods of intrusion detection that these systems use, all with their own benefits and drawbacks. These include signature-based detection and anomaly-based detection, both of which have their own set of advantages and disadvantages.

Signature-Based Detection

Signature-based detection is a type of intrusion detection system that uses known signatures of malicious activity to identify threats. Similar to what is found in commercial antivirus products, this type of detection looks specifically for pre-programmed behaviors that indicate a threat, such as malicious domains, byte sequences, or communication headers. Because signature-based detection is limited to existing threats, it is a poor solution for identifying zero-day exploits and other unique methods of attack; however, the false-positive rate can typically be lower due to the “already known” nature of the detection method.

Anomaly-Based Detection

Anomaly-based detection is a type of intrusion detection system that uses machine learning to identify suspicious activity. Rather than looking for known threats, these systems establish and maintain a baseline signature for system activity and notify administrators when any of that activity deviates from that norm. Anomaly-based detection has the potential for a high false-positive rate until that baseline is properly understood, but is a far more effective detection method when an organizational threat model is concerned about the type of zero-day exploits that signature-based detection is insufficient to address.

Challenges and limitations of Intrusion Detection in the Cloud

One of the biggest factors that might limit the effectiveness of any cloud intrusion detection system is the quantity and quality of the data it is able to access. As you can imagine, the more data that is available to the system, the more information it has to work with, which translates to a higher likelihood of malicious activity being properly caught and contained.

But data access is only one potential issue. Hybrid and multi-cloud deployments can be particularly challenging to secure with an intrusion detection system, and even single-cloud deployments can become difficult to expand beyond due to the risk of vendor lock-in.

Vendor Lock-In

While there is often no better intrusion detection provider for any given cloud than the cloud providers themselves, the risk of vendor lock-in can make infrastructure portability difficult. Cloud vendors all have their own security policies and tools that integrate nicely with their underlying systems. But that makes it difficult to configure an intrusion detection system that works across multiple cloud providers or even to migrate from one cloud provider to another. A provider-agnostic solution might be more portable, but might also be less effective, so the trade-off is not always obvious.

Multi-Cloud Intrusion Detection

Hybrid and multi-cloud environments present unique challenges for intrusion detection systems due to the potential lack of data uniformity and access levels. When data is spread across multiple cloud providers, it can be difficult for the system to access all the data necessary to identify malicious activity or even correlate access patterns across multiple systems. Additionally, different cloud providers may have different security policies, making it especially challenging to implement a consistent security strategy across multiple providers. Finally, access problems might make integrating both cloud-based and on-prem intrusion detection difficult as well.

Best Practices for implementing Intrusion Detection in the Cloud

Despite some of the challenges, the benefits of utilizing intrusion detection in the cloud far outweigh the risks. In order to set yourself up for success when implementing an intrusion detection system in the cloud, there are several best practices that are worth keeping in mind. First (and most obvious), organizations should ensure that the system is properly configured and regularly monitored and maintained. What’s the point in having a home security system if you never turn it on, right?

Additionally, organizations need to ensure that the system is able to access all the data necessary to detect malicious activity using whatever detection method is available. In the event of behavioral detection, keeping the vulnerability signatures up to date is just as important as changing the oil in your car, and with anomaly detection, it is critical to take the time and care necessary to properly tune your baselines to prevent false positives and protect your team from alert fatigue and developers’ fatigue.

Next steps

While cloud intrusion detection is a vital part of the cloud security puzzle, it is important to remember that it is not the only element to consider. A tool is only as powerful as the person using it, so it is essential to ensure that members of your organization are not only trained in the operation and maintenance of your intrusion detection system, but also engaged in continuous professional development activities to make sure their skills are sharp and that they are ready and able to respond to any incidents as they arise.