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With any service providing a security check on your systems it’s important to monitor its activity. This lecture looks at how AWS CloudWatch can be used to monitor specific metrics to help you determine the effectiveness of your WAF solution. The lecture also covers how AWS SNS (Simple Notification Service) along with AWS CloudWatch can be used to create a reactive rule set rather than a static one.


Hello and welcome to this lecture regarding monitoring your WAF service.

As a pre-requisite of this lecture, you should have a basic understanding of AWS Simple Notification Serviceand AWS CloudWatch. For more information on CloudWatch, we have a lab which will guide you through an introduction to the service which can be found in the link on the screen.

If you decide to monitor what your WAF service is doing and how it's performing, then there are a range of features that allow you to do this. However, as with any monitoring you want to conduct, you need to make sure you know what you're monitoring it for, what is the purpose of the monitoring, also how often you intend to monitor and what elements of the service you want to monitor.

Are you looking to perform monitoring to maintain reliability and operational performance or are you looking to understand trends allowing you to implement additional controls making your infrastructure even more secure? Once you know what you are monitoring and why, it becomes easier to select the best approach. And this is true for all monitoring.

Let's start with the service itself. From within the AWS WAF service dashboard in the management console, you are able to view certain statistical information for the web ACLs you have created. You can't generate reports from here. However, the service dashboard does provide a graphical view of the request that match each of your rules within your web ACLs along with the total number of requests.

For additional monitoring functionality and features, you can use AWS CloudWatch. As I mentioned in a previous lecture, WAF integrates well with AWS CloudWatch, allowing you to monitor set metrics for the service. WAF CloudWatch metrics are reported in one-minute intervals by default. The metrics monitored are AllowedRequests, BlockedRequests and CountedRequests.

These are all very much self-explanatory. However, these metrics provide a sum count of web requests that hit a specific rule or web ACL.

You may have noticed during the demo I gave earlier that on the first step of configuration of the WAF service, you were asked to enter a name for the web ACL. At the same time, the service is automatically generating a CloudWatch metric name with the same name to allow you to report statistics against the web ACL.

For each web ACL you have, there will be an associated CloudWatch metric and the same applies to WAF rules. From AWS CloudWatch, you can perform all the same functions as with other services that you monitor such as alarm creation and viewing the history from the graphical interface.

If you are creating a reactive policy within your web ACL, instead of a whole host of static pre-configured rules that can get a little difficult to manage, then you could set a count action for a number of rules that you have configured. From within CloudWatch, you could then set an SNS notification to alert the security team to change the relevant rule action to either allow or block as required. Setting reactive rules could help reduce the number of rules within your web ACL and reduce the number of false positives that can occur more with larger rule sets.

That brings us to the end of this lecture. Coming up next, we look at the limitations associated with AWS WAF.



About the Author
Learning paths61

Stuart has been working within the IT industry for two decades covering a huge range of topic areas and technologies, from data center and network infrastructure design, to cloud architecture and implementation.

To date, Stuart has created 80+ courses relating to Cloud reaching over 100,000 students, mostly within the AWS category and with a heavy focus on security and compliance.

Stuart is a member of the AWS Community Builders Program for his contributions towards AWS.

He is AWS certified and accredited in addition to being a published author covering topics across the AWS landscape.

In January 2016 Stuart was awarded ‘Expert of the Year Award 2015’ from Experts Exchange for his knowledge share within cloud services to the community.

Stuart enjoys writing about cloud technologies and you will find many of his articles within our blog pages.