[Owasp-o2-platform] Finally ... here is how I have been analysing Spring MVC apps using O2

dinis cruz dinis.cruz at owasp.org
Mon Jul 11 22:05:45 EDT 2011


One of the greatest challenges I always had when reviewing Spring MVC
applications, was to gain a ful picture of its controllers, and more
importantly its CommandClasses (i.e. the POJOs that are AutoBinded by Spring
and who are a common source of high/critical vulnerabilities in Spring MVC
apps).

The way I approach these problems (visualizing/understanding Spring, Struts,
DWR, Sharepoint, etc...), is to write scripts that consume the Application's
articfacts (web.xml, *-servlet.xml, source-code, class files) and then
consolidated that information in 'easy' (or easier) to undersand
visualizations.

Unfortunally most of the great examples that I had in the past were built on
top of Client code, so I couldn't really share them. But finally, the O2
Scripts have reached a level of maturity that it was easy to create a
generic version of them for Spring's MVC Demo application: *JPetStore*.

Ironically, this demo application from Spring (which is used by Spring
Developers to learn how ot use Spring), is actually vulnerable to a number
of security issues, including some spectacular cases of the Spring MVC
AutoBinding issue.

I have created a number of Blog posts and videos that hopefully will help
you to understand (and replicate) the issue:

   - O2 Script with BlackBox exploits for Spring MVC AutoBinding
   vulnerabilities in
JPetStore<http://o2platform.wordpress.com/2011/07/11/o2-script-with-blackbox-exploits-for-spring-mvc-autobinding-vulnerabilities-in-jpetstore/>(with
video) - Blog post that shows a number of security exploits in action,
   for example: *create a shopping cart, to though the payment process, and
   change the total value on the last step*
   - O2 Script: ‘Spring MVC Util – View
Controllers’<http://o2platform.wordpress.com/2011/07/12/o2-script-spring-mvc-util-view-controllers/>(with
video) - Blog post that presents a visualizer for the Spring MVC
   mappings. *This is the most imporant script here* , since this is the
   view that is really unique (and the one I have not seen anywhere else). What
   you have there is a full mapping of the Spring MVC properties for JPetStore,
   which includes not only the 'URL to Controller' mappings, but (much more
   important) a 'expanded' view of the CommandClass. And altough the JPetStore
   example is already quite a good one, in the real world these POJO objects
   tend to be massive (with cases where the developers/management only expects
   that only a couple fields should be populated form an HTTP request, and in
   reality, dozens if not hundreds of fileds can be edited/manipulated)
   - O2 Script for “Spring MVC JPetStore – Start Servers” (start/stop apache
   and hsqldb)<http://o2platform.wordpress.com/2011/07/12/o2-script-for-spring-mvc-jpetstore-start-servers-startstop-apache-and-hsqldb/>(with
video) - Blop post that shows an O2 Script that starts the apache and
   hsqldb server
   - http://s3.amazonaws.com/Demo_Files/jPetStore%20-%20O2%20Demo%20Pack.zip
- Fully
   packaged version of JPetStore and relevant O2 Scripts (it is 30Mb because it
   includes apache server)
   -
   http://diniscruz.blogspot.com/2011/07/two-security-vulnerabilities-in-spring.html
-
   Blog post with a couple more details about the Spring MVC AutoBinding
   vulnerability (exploited above) and a link to the 2008 white paper published
   on this topic

The other important factor about these examples, is that I finally have a
real example that can be used when talking with the Spring Framework
team, other OWASP/AppSec FOSS tools and with AppSec vendors (tools and
service-providers). Basically, from now on the message is: *here is a
complete scenario, now lets figure out how to use your technology to fix,
detect or mitigate this.*

*This is also a part of O2 that I was waiting for, in order to be able to
fully participate in the current OWASP 'reach the developer' efforts.* In
order to reach the developers, we need to speak their language, and with
these examples (and technology) I can finally communicate properly with
developers, and show them how their app works.

Note that the point here is not to push that everybody should be using using
O2 to perform this type of analysis!   My objective with O2 is to show what
can/should be done, and to allow others to create more native
implementations of these techniques (in this case, there should be an
eclipse plug-in to do this or to consume this data). Ultimately if we want
to reach the developers we need to communicate with them using tools and
techniques they are already used to.

There is still a lot to document and to map out (including other tools that
merge even further the black-box and white box worlds), so please take these
scripts for a test drive, *and help me to create a really powerful 'Spring
MVC Security Analsys ToolKit' that can dramatically increase the security of
Spring MVC applications :)*

We also need to start thinking about *creating an (Open) 'Spring MVC
Security Rule Pack' which can be maintained by the community and consumed by
the multiple tools/services*.

Final note for the .NET Crowd, *the ASP.NET MVC has the same problem*, and I
although I have not looked at a big ASP.NET MVC app, I will bet that they
will create the same types of vulnerabilties (so ...  if you have access to
such an app, try the O2's ASP.NET MVC visualizer on it :)  )

Dinis Cruz
Blog: http://diniscruz.blogspot.com
Twitter: http://twitter.com/DinisCruz
Web: http://www.owasp.org/index.php/O2
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