SEO/Security/Sysadmin tools: Web application detection

I’m knee deep in web development. I also always like to look at websites from a security point of view. This often means I end up looking at http headers, source code, error pages and so on to see what software a site is running and what its vulerabilities might be.

Eventhough this may sound like an odd hobby, I bet there are other people who do something similar, and to save me and those others some time I’ve written two tools to help in figuring out what kind of software a site is running: Fetch, a tool to fetch and analyze HTTP headers / responses and Guess, a tool to detect the web software stack used on a site

I hope these tools can be of use to web developers, SEO consultants and security consultants, or just anyone who’s interested in seeing what’s happening behind the (browser) screens

All of this has also allowed me to develop a powerful toolkit to scan/analyze websites which I plan to use for other future projects, SEO and security related, but I can for example also imagine an ISP may find it useful to analyze what kind of software their users are actually running


I’ve blogged about Fetch before so I won’t get into too much detail. It’s basically the web equivalent of telnet host.tld 80 and doing a GET or HEAD by hand, but then a lot more user friendly, verbose and feature-rich.


Guess analyzes a site and tries to figure out what Webserver, language and framework a site is running. If possible, it will also attempt to find the versions used

Guess is learning about new software stacks each day and it already has an impressive hit rate (at least the sites that I usually try it on), though some very obvious systems still aren’t detected.

I’ve also planned much more features such as

  • Javascript library detection
  • Details about stats tools used
  • OS details
  • Plugins, options, modules used/installed

Currently, it detects a large range of CMS’s and frameworks, open and close source, such as:

  • Wordpress
  • Drupal
  • Joomla
  • Zope, Plone (of course ;)
  • Zine (duh!)
  • Django
  • Squarespace
  • GX
  • MovableType
  • Ruby on rails
  • And many more (and adding new ones each eh.. week)…
Bookmarklets, extensions

Both tools can be used as bookmarklets, simply copy the url to your bookmarks toolbar and clicking it will open the site you have open a new window with either Fetch or Guess

I’m also planning on developing simple Chrome and Firefox extensions, but adding more software stacks and features have a higher priority; the bookmarklets actually work really well.

Last updated April 18, 2013, 4:35 p.m.
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