Re: [WEB SECURITY] Preventing Cross-site Request Forgeries [ASP.NET crowd]

["Chris Weber" <chris () lookout net>]

Actually that's not true.  We should be clear that this is *not* the same
thing as ViewStateUserKey (which is not enabled by default).
EnableEventValidation does provide postback input related protections, but
ViewStateUserKey actually ties it to the user session.  Without
ViewStateUserKey, you will notice the __EVENTVALIDATION nonce will be the
same for any two users.  With ViewStateUserKey, the value will be unique per
user.



-----Original Message-----
From: Michael Sutton [mailto:msutton () spidynamics com] 
Sent: Friday, March 30, 2007 3:59 PM
To: Chris Weber; pdp (architect); full-disclosure () lists grok org uk; WASC
Forum; webappsec @OWASP
Subject: RE: [WEB SECURITY] Preventing Cross-site Request Forgeries [ASP.NET
crowd]

The EnableEventValidation page directive (enabled by default since .Net
2.0) applies a nonce value for form validation and is also a strong control
to prevent CSRF attacks. 

Michael Sutton
Security Evangelist
SPI Dynamics
http://portal.spidynamics.com/blogs/msutton

> -----Original Message-----
> From: Chris Weber [mailto:chris () lookout net]
> Sent: Friday, March 30, 2007 6:12 PM
> To: 'pdp (architect)'; full-disclosure () lists grok org uk; 'WASC
Forum';
> 'webappsec @OWASP'
> Subject: RE: [WEB SECURITY] Preventing Cross-site Request Forgeries 
> [ASP.NET crowd]
>
> Nice article.
>
> For the ASP.NET crowd out there, the will be even more simple, one
line of
> code.  Set the ViewStateUserKey property in your base class or page
and
> the
> unique token protections (similar to CSRF_Guard) will be provided for
you.
> http://msdn2.microsoft.com/en-
> us/library/system.web.ui.page.viewstateuserkey
> .aspx
>
> This protection mechanism has been available for many years, since the 
> Framework 1.1
>
>
>
>
>
> -----Original Message-----
> From: pdp (architect) [mailto:pdp.gnucitizen () googlemail com]
> Sent: Friday, March 30, 2007 3:16 AM
> To: full-disclosure () lists grok org uk; WASC Forum; webappsec @OWASP
> Subject: [WEB SECURITY] Preventing Cross-site Request Forgeries
>
> http://www.gnucitizen.org/blog/preventing-csrf
>
> I briefly covered how simple it is to prevent CSRF attacks. Hope that
you
> find it useful.
>
> --
> pdp (architect) | petko d. petkov
> http://www.gnucitizen.org
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