First look at Web Application Scanner (WAS)

When Tenable firstly announced Web Application Security scanner as a part of their new platform, it was quite intriguing. Certainly, they already had some WAS functionality before in Nessus. For example, path traversal check was pretty good. But this functionality was quite fragmental and barely manageable. How Tenable now write in their docs: “Nessus is incompatible with modern web applications that rely on Javascript and are built on HTML5”.

First look at Web Application Scanner (WAS)

That’s why Nessus couldn’t be called fully functioning Web Application Scanning solution. However, WAS is a completely new story. The full description is available on official site. Here I will make a very fast review and give some comments.

Trial Request

I used a trial version. You can use it for free for 60 days. Trial registration is fully automatic, just fill the form and choose “Try Web Application Scanning”. You can create trial in various locations: US, UK, Germany, Singapore and Australia. Than check your inbox to verify your email address and set the password.

The evaluation version contains three products:

  • Container Security
  • Vulnerability Management
  • Web Application Scanning

Next you will need to accept License Agreement and GDPR alignment. And that’s it.

Tenable IO Login GUI

Just like in VM, the main page in WAS contains a dashboard with statistics on vulnerability severity, types of vulnerabilities and vulnerability dynamics.

Tenable IO WAS Dashboard

Web App Scan policy

The WAS is now integrated in familiar Nessus-like interface of Basically, it’s no more than a specific scan profile.

Tenable IO WAS Template

It seems like custom profiles are now the main way for adding new functionality in Tenable scanning products. Check this profile with dynamic plugin sets. I really like this, it creates great and holistic user experience.

New Web App Scan

Here is how Web App Scan looks like. You can choose name, target, folder for the scan an Scanner location (Frankfurt, Singapore and US).

Tenable IO WAS Scan


It’s awesome, that Tenable IO WAS allows to see the plugins that will be executed during the scan and enable/disable them. Just like Nessus. Most of the plugins (528) are version-based checks. You can search them by id on the Tenable plugins site, for example AngularJS 1.3.0 < 1.5.0-rc.2 Cross-site Scripting.

Tenable IO Web App Scan Plugins


For HTTP Server you can set Basic/Digest or NTLM authentication:

Tenable IO WAS HTTP Server Authentication

For Web Application it’s trickier. WAS now supports 3 authentication methods: Login Form, Cookie and Selenium. All of them have mandatory fields “Page to verify active session” and “Regex to verify active session”. It’s the way how Tenable IO WAS understand that the session is still active. Pretty simple and reliable. For the Login Form there is also a regex to verify that the authentication operation was successful.

Login Form:

Tenable IO WAS Web Application Authentication Login


Tenable IO WAS Web Application Authentication Cookie


Tenable IO WAS Web Application Authentication Selenium

Other Settings

What else can we edit in Settings? Like with the Nessus scan, there is the ability to schedule scan, set notifications and permissions. Besides that:

  • In Scope you can set URLs that should be included and excluded from the scan. You can exclude them by regex or file extension. Here you can also limit crawling: only specified URLs or specified URLs with child paths.
  • In Discovery you can set Crawl Selenium Scripts.
  • In Assessment you can choose elements that you want to Assess (cookies, forms, headers, links, parameter names, parameter values, JSON, XML, UI Forms, UI Inputs) or preset from this elements (Quick or Extensive).
  • In Advanced you can set various time limits (Overall Scan time, various timeouts) and limits on number of operations (number of request, connections, URLs, depth etc.). Note that in Discovery sub-tab you can set custom User Agent and Header, that could be used for giving access to the application and filtering scanner activity.
Tenable IO WAS Crawling Settings

Scan Results

Result of the scan looks pretty much like in Nessus:

Plugin output is combined by URLs and contains text output and attached files with the details:

In conclusion

The scanner looks great. I liked that they use Selenium for authentication and crawling. The only thing that I found confusing is authentication management in Credentials. It requires specifying URLs & regexs or script. It would be nice to debug these settings directly in the application settings interface, like in Nexpose VM. I’ll not write anything about the scan quality yet, it takes more time for testing.

6 thoughts on “First look at Web Application Scanner (WAS)

  1. Pingback: Tenable IO WAS Chrome Extension | Alexander V. Leonov

  2. Gary Miller

    Hello Alexander,

    Did you complete the Tenable WAS testing – it would be interesting to hear your thoughts an findings.


  3. Dhruv Bhatnagar

    I have a web application in which I have Login Parameteres -> CSRF token + username +password
    How do I pass the csrf token in nessus while doing web app scan?

  4. doiki

    Because the tool is implementing a dynamic testing method, it cannot cover 100% of the source code of the application and then, the application itself. The penetration tester should look at the coverage of the web application or of its attack surface to know if the tool was configured correctly or was able to understand the web application.


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