on 05-May-2020 15:06
Whether you are a beginner or an expert, there is a truth that I want to let you in on; building and maintaining Web Application Firewall (WAF) security policies can be challenging. How much security do you really need? Is your configuration too much or too little? Have you created an operational nightmare?
Many well-intentioned administrators will initially enable every available feature, thinking that it is providing additional security to the application, when in truth, it is hindering it. How, you may ask? False positives and noise. The more noise and false positives, the harder it becomes to find the real attacks and the increased likelihood that you begin disabling features that ARE providing essential security for your applications. So… less is better then? That isn't the answer either, what good are our security solutions if they aren't protecting against anything? The key to success and what we will look at further in this article, is implementing best practice controls that are both measurable and manageable for your organization.
The OWASP Application Security Top 10 is a well-respected list of the ten most prevalent and dangerous application layer attacks that you almost certainly should protect your applications from. By first focusing your security controls on the items in the OWASP Top 10, you are improving the manageability of your security solution and getting the most "bang for your buck". Now, the challenge is, how do you take such a list and build real security protections for your applications?
Protecting your applications against the OWASP Top 10 is not a new thing, in fact, many organizations have been taking this approach for quite some time. The challenge is that most implementations that claim to "protect" against the OWASP Top 10 rely solely on signature-based protections for only a small subset of the list and provide zero insight into your compliance status.
The OWASP Compliance Dashboard introduced in version 15.0 on BIG-IP Advanced WAF reinvents this idea by providing a holistic and interactive dashboard that clearly measures your compliancy against the OWASP Application Security Top 10. The Top 10 is then broken down into specific security protections including both positive and negative security controls that can be enabled, disabled, or ignored directly on the dashboard. We realize that a WAF policy alone may not provide complete protection across the OWASP Top 10, this is why the dashboard also includes the ability to review and track the compliancy of best practices outside the scope of a WAF alone, such as whether the application is subject to routine patching or vulnerability scanning.
To illustrate this, let’s assume I have created a brand new WAF policy using the Rapid Deployment policy template and accepted all default settings, what compliance score do you think this policy might have? Let's take a look.
Interesting. The policy is 0/10 compliant and only A2 Broken Authentication and A3 Sensitive Data Exposure have partial compliance. Why is that? The Rapid Deployment template should include some protections by default, shouldn't it? Expanding A1 Injection, we see a list of protections required in order to be marked as compliant. Hovering over the list of attack signatures, we see that each category of signature is in 'Staging' mode, aha! Signatures in staging mode are not enforced and therefore cannot block traffic. Until the signature set is in enforced, we do not mark that protection as compliant. For those of you who have mistakenly left entities such as Signatures in staging for longer than desired, this is also a GREAT way to quickly find them. I also told you we could also interact with the dashboard to influence the compliancy score, lets demonstrate that.
Each item can be enforced DIRECTLY on the dashboard by selecting the "Enforce" checkmark on the right. No need to go into multiple menus, you can enforce all these security settings on a single page and preview the compliance status immediately. If you are happy with your selection, click on "Review & Update" to perform a final review of what the dashboard will be configuring on your behalf before you can click on "Save & Apply Policy".
Note: Enforcing signatures before a period of staging may not be a good idea depending on your environment. Staging provides a period to assess signature matches in order to eliminate false positives. Enforcing these signatures too quickly could result in the denying of legitimate traffic.
Let's review the compliancy of our policy now with these changes applied. As you can see, A1 Injection is now 100% compliant and other categories have also had their score updated as a result of enforcing these signatures. The reason for this is because there is overlap in the security controls applied across these other categories.
Not all security controls can be fully implemented directly via the dashboard, and as mentioned previously, not all security controls are signature-based. A6 Cross-Site Scripting was recalculated as 50% complaint with the signatures we enforced previously so let's take a look at what else it required for full compliancy.
The options available to us are to IGNORE the requirement, meaning we will be granted full compliancy for that item without implementing any protection, or we can manually configure the protection referenced. We may want to ignore a protection if it is not applicable to the application or if it is not in scope for your deployment. Be mindful that ignoring an item means you are potentially misrepresenting the score of your policy, be very certain that the protection you are ignoring is in fact not applicable before doing so.
I've selected to ignore the requirement for "Disallowed Meta Characters in Parameters" and my policy is now 100% compliance for A7 Cross-Site Scripting (XSS).
Lastly, we will look at items within the dashboard that fall outside the scope of WAF protections. Under A9 Using Components with Known Vulnerabilities, we are presented with a series of best practices such as “Application and system hardening”, “Application and system patching” and “Vulnerability scanner integration”. Using the dashboard, you can click on the checkmark to the right for "Requirement fulfilled" to indicate that your organization implements these best practices. By doing so, the OWASP Compliance score updates, providing you with real-time visibility into the compliancy for your application.
The OWASP Compliance Dashboard on BIG-IP Advanced WAF is a perfect fit for the security administrator looking to fine-tune and measure either existing or new WAF policies against the OWASP App Security Top 10. The OWASP Compliance Dashboard not only tracks WAF-specific security protections but also includes general best practices, allowing you to use the dashboard as your one-stop-shop to measure the compliancy for ALL your applications. For many applications, protection against the OWASP Top 10 may be enough, as it provides you with best practices to follow without having to worry about which features to implement and where.
Note: Keep in mind that some applications may require additional controls beyond the protections included in the OWASP Top 10 list.
For teams heavily embracing automation and CI/CD pipelines, logging into a GUI to perform changes likely does not sound appealing. In that case, I suggest reading more about our Declarative Advanced WAF policy framework which can be used to represent the WAF policies in any CI/CD pipeline. Combine this with the OWASP Compliance Dashboard for an at-a-glance assessment of your policy and you have the best of both worlds.
If you're not already using the OWASP Compliance Dashboard, what are you waiting for?
Look out for Bill Brazill, Victor Granic and myself (Kyle McKay) on June 10th at F5 Agility 2020 where we will be presenting and facilitating a class called "Protecting against the OWASP Top 10". In this class, we will be showcasing the OWASP Compliance Dashboard on BIG-IP Advanced WAF further and providing ample hands-on time fine-tuning and measuring WAF policies for OWASP Compliance. Hope to see you there! To learn more, visit the links below.