phpBBXSS206d.txt

`Vendor : phpBB Group  
URL : http://www.phpbb.com  
Version : phpBB 2.0.6d && Earlier  
Risk : Cross Site Scripting  
  
  
  
Description:  
phpBB is a high powered, fully scalable, and highly customisable open-source   
bulletin board package. phpBB has a user-friendly interface, simple and straight   
forward administration panel, and helpful FAQ. Based on the powerful PHP server   
language and your choice of MySQL, MS-SQL, PostgreSQL or Access/ODBC database   
servers, phpBB is the ideal free community solution for all web sites.  
  
  
  
Problem:  
phpBB is a great forum system used by many millions of people. It is one of   
the more secure of the forum systems, but has a few issues still present; both   
of which allow for XSS (Cross Site Scripting). This problem presents itself in   
two different places.One of these places is viewtopic.php and the other is   
viewforum.php Below are examples along with a brief explanation on how to   
replicate this issue.  
  
viewforum.php?f=[FNUM]&topicdays=[DNUM][XSS]  
  
FNUM is a valid forum number. DNUM is the number of days to check. If you get no   
results with the number 1 for example try the number 99 and so forth and so on.   
XSS is whatever code is injected.  
  
viewtopic.php?t=[TNUM]&postdays=[DNUM][XSS]  
  
This is nearly the same issue as above, it just happens to be present in multiple   
files. The only difference is TNUM is a valid topic id number. Remember, the query   
must display results in order for the XSS to take place. Additionally the offset   
(start) variable may be used to get results, but in most cases is unnecessary.   
Examples are below though.  
  
  
  
Examples:  
viewforum.php?f=1&topicdays=99"><script>alert(document.cookie)</script>&start=30  
viewtopic.php?t=10&postdays=99"><script>alert(document.cookie)</script>&start=20  
  
  
  
Solution:  
I have released a fix for this vulnerability. It requires a valid integer for the  
affected variables, and thus eliminates this vulnerability from taking place. You  
can find the fix by following the link below.  
  
http://www.gulftech.org/vuln/phpBB2.0.6dfix.rar  
  
Alternatively you can do it yourself by following the instructions listed below.  
  
  
-----[ OPEN ]-----------------------------------  
  
viewforum.php  
  
-----[ FIND ]-----------------------------------  
  
if ( !empty($HTTP_POST_VARS['topicdays']) || !empty($HTTP_GET_VARS['topicdays']) )  
{  
$topic_days = ( !empty($HTTP_POST_VARS['topicdays']) ) ? $HTTP_POST_VARS['topicdays'] : $HTTP_GET_VARS['topicdays'];  
$min_topic_time = time() - ($topic_days * 86400);  
  
-----[ REPLACE WITH ]---------------------------  
  
if ( !empty($HTTP_POST_VARS['topicdays']) || !empty($HTTP_GET_VARS['topicdays']) )  
{  
  
///////////////////////////////////////////////////////////////////  
// Lets Do Away With These Problems By Requiring A Valid Integer //  
// Fix By JeiAr // http://www.gulftech.org // Friday 03 12, 2004 //  
///////////////////////////////////////////////////////////////////  
  
$topic_days = ( !empty($HTTP_POST_VARS['topicdays']) ) ? intval($HTTP_POST_VARS['topicdays']) : intval($HTTP_GET_VARS['topicdays']);  
$min_topic_time = time() - ($topic_days * 86400);  
  
  
  
  
  
-----[ OPEN ]-----------------------------------  
  
viewtopic.php  
  
-----[ FIND ]-----------------------------------  
  
if( !empty($HTTP_POST_VARS['postdays']) || !empty($HTTP_GET_VARS['postdays']) )  
{  
$post_days = ( !empty($HTTP_POST_VARS['postdays']) ) ? $HTTP_POST_VARS['postdays'] : $HTTP_GET_VARS['postdays'];  
$min_post_time = time() - (intval($post_days) * 86400);  
  
-----[ REPLACE WITH ]---------------------------  
  
if( !empty($HTTP_POST_VARS['postdays']) || !empty($HTTP_GET_VARS['postdays']) )  
{  
  
///////////////////////////////////////////////////////////////////  
// Lets Do Away With These Problems By Requiring A Valid Integer //  
// Fix By JeiAr // http://www.gulftech.org // Friday 03 12, 2004 //  
///////////////////////////////////////////////////////////////////  
  
$post_days = ( !empty($HTTP_POST_VARS['postdays']) ) ? intval($HTTP_POST_VARS['postdays']) : intval($HTTP_GET_VARS['postdays']);  
$min_post_time = time() - (intval($post_days) * 86400);  
  
  
  
  
  
phpBB development team will be releasing an official fix soon. Please check their   
website, or the SourceForge projects page of phpBB for any updates. The SourceForge   
projects page for phpBB can be located @ http://sourceforge.net/projects/phpbb The   
fix supplied here should suffice though. If you feel this is incorrect please contact   
me with details of any problems you experience. And a big thanks to Meik Sievertsen   
and the rest of the phpBB team for addressing these issues in a very prompt and   
professional manner. Original advisory located @ http://www.gulftech.org/03122004.php  
  
  
  
Credits:  
Credits go to JeiAr of the GulfTech Security Research Team.   
http://www.gulftech.org  
  
`