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Microsoft IIS 6 parsing directory “x.asp” Vulnerability


From: info () securitylab ir
Date: 25 Jan 2011 18:13:50 -0000

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# Microsoft IIS 6 parsing directory Vulnerability
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#Discovered by: 
Pouya daneshmand
whh_iran[AT]yahoo[DOT]com
http://securitylab.ir/blog

#Introduction:
Using this vulnerability you can bypass some Security filters, for example a file with “.jpg” or “.rar” extension can 
be executed as an asp (Active Server Page) file.

#Vulnerable:
It just works for asp files and works on Windows 2003 / IIS 6 (As I tested...).
The test failed on IIS 5.1 and IIS 7.


#Description:
1) Create a Folder with '.asp' extension.
2) Insert your ASP code in a file with any extension (like .jpg,.rar,.txt) in the folder you have created.
3) Open the file with your browser and you will see it's executed as an asp file!

#Note:
The Extension of file does not matter at all!


#Solution:
There is no patch to fix this security vulnerability yet, the best thing I can say is to DISABLE ASP FILES FROM YOUR 
"web server extensions"! Or Remove “execute” permission from the upload directories.



#PS:
This vulnerability was reported for first time at 2010-06-19 in Persian (http://sebug.net/vulndb/19820/)

#Original Advisory:
http://securitylab.ir/blog/dl/Microsoft-IIS6-parsing-directory-Vulnerability.pdf
http://securitylab.ir/blog/posts/11/Microsoft-IIS-6-parsing-directory-%E2%80%9Cx.asp%E2%80%9D-Vulnerability/


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