From: Dinis Cruz (dinis@ddplus.net)
Date: Tue Sep 14 2004 - 18:08:30 EDT
If the code is running with full trust it can call RevertToSelf() and change
the current Asp.Net (Thread) Identity into the Process' Identity (which
belongs to the IIS_WPG).
Once this is done:
1) You can probably already bypass several NTFS restrictions and see other
website's data (and other sensitive information usually left on the server)
2) You can read (from the Metabase) other website's Anonymous and
Application Pool Account details (Username and Password), use that
information to impersonate those users (which you can with Full Trust) and
access other website's data
3) If other websites share the same application pool, you can search the
current w3wp process for their security tokens, use those tokens to
impersonate those users (no need to know their password) and access
website's data
4) You can upload to the server an exploit and execute it. With full trust
it is almost impossible to stop the upload and execution of a malicious
.EXE. The only defence could be if the Anti-Virus installed on the server is
able to detect the Malware (although this limitation could be easily
bypassed by any half-decent malicious attacker with access to the exploit's
source code)
5) etc, etc, etc..... There any many more attack vectors, but these should
be enough to make my point
Note that even if the attacker is only able to gain read access to another
website's data, most likely he/she will be able to retrieve the Database
Connection String and gain FULL access to that website's database.
If this is news for you (i.e. how dangerous Full Trust Asp.Net can be), then
I would recommend that you take a good look at the work I have done over the
last year at OWASP (Open Web Application Security Project), namely Open
Source tools: ANSA (Asp.Net Security Analyser) and SAM'SHE (Security
Analyser for Microsoft's Shared Hosting Environment).
Some links:
- OWASP .NET section: http://www.owasp.org/software/dotnet.html
- Post with Links to some of my online posts (Security issues with Asp.Net
in Shared Hosting Environments, OWASP .Net tools and OWASP AppSec
Presentation):
http://sourceforge.net/mailarchive/forum.php?thread_id=5203278&forum_id=2475
4
- presentation that I did last June at the OWASP AppSec NYC 2004 conference
entitled "Full Trust Asp.Net (in)Security / Secure Asp.Net Web Application
Development":
-
http://prdownloads.sourceforge.net/owasp/AppSec2004-Dinis_Cruz-Full_Trust_As
p.Net_Security_Issues.ppt?download (main PPT)
-
http://prdownloads.sourceforge.net/owasp/AppSec2004-Dinis_Cruz-Full_Trust_Vi
deos.zip?download (the support videos: "ANBS - SamShe.avi", "ANBS - XML
database and Metabase explorer.avi", "IIS Security Token Vulnerability.avi",
"ANSA - Run tests individually.avi", "ANSA - Security Analyser.avi")
Best Regards
Dinis Cruz
.Net Security Consultant
DDPlus
> -----Original Message-----
> From: Ken Schaefer [mailto:ken@adopenstatic.com]
> Sent: 14 September 2004 03:10
> To: webappsec@securityfocus.com; pen-test@securityfocus.com
> Subject: RE: Apache VS IIS Securiyt model question
>
> I'm pretty sure that Mike is talking about NTFS permissions (and Windows
> users and groups). Can you point us to how ASP.NET code running as fully
> trusted gets around that?
>
> Cheers
> Ken
>
> -------- Original Message --------
> > From: "Dinis Cruz" <dinis@ddplus.net>
> > Subject: RE: Apache VS IIS Securiyt model question
> >
> > Please note that these security settings will only be relevant (in IIS)
> in a
> > Partially Trusted Website (i.e. the Asp.Net code is NOT running with
> Full
> > Trust).
> >
> > If the code is running with Full Trust, then most likely those security
> > permissions will be easily bypassed.
> >
> > Dinis Cruz
> > .Net Security Consultant
> > DDPlus
> >
> > > -----Original Message-----
> > > From: mthompson [mailto:mthompson@brinkster.com]
> > > Sent: 11 September 2004 01:56
> > > To: webappsec@securityfocus.com; pen-test@securityfocus.com
> > > Subject: Apache VS IIS Securiyt model question
> > >
> > > Hello,
> > >
> > > I am doing research and I am stuck.
> > >
> > > Pitch: In IIS there is the ability to set permissions on a per website
> > > basis. In other words the ability to limit access to files and
> > > directories based on the users credentials that the website is running
> > > under. Additionally, you would in turn add this user to a group and
> > > apply group permissions to an object that needed to be accessed by
> more
> > > than one site.
> > >
> > > Question: Is there a similar security model for apache that would
> allow
> > > credentials from a user to run a virtual website and access files only
> > > for a specific virtual site.
> > >
> > > Also, does any one have a diagram of the apache process?
> > >
> > > Thanks,
> > >
> > > Mike
> > >
>
>
>
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