[KAPDA::#6] Punbb SQL Injection Vulnerability

[advisory@xxxxxxxx]

[KAPDA::#6] Punbb SQL Injection Vulnerability

Punbb search.php SQL Injection Vulnerability

KAPDA New advisory

Vulnerable products : Punbb ( V 1.2.8 and 1.2.7 are tested,Hopefully all other 
versions) 

Vendor: http://www.punbb.org/

Vulnerability: Sql injection

About Punbb
--------------------
   PunBB is a fast and lightweight PHP-powered discussion board. It is released 
under the GNU 

General Public License. Its primary goals are to be faster, smaller and less 
graphically intensive

as compared to other discussion boards. PunBB has fewer features than many 
other discussion

boards, but is generally faster and outputs smaller, semantically correct 
XHTML-compliant pages.

        Vendor`s description : http://punbb.org/about.php

Discussion :
----------------
  Scripts in page "Search.php" do not properly validate user-supplied input. A 
remote user can

create specially crafted parameter values that will execute SQL commands on the 
underlying

database.

  While "Global_register" of php.ini is set ON ,Remote user can poison local 
variables

of PHP pages to take control of web application or change its logical flow.
 
Vulnerabilities:
--------------------
In Search.php :

.......... start ...........

if ($db->num_rows($result))
{
while ($row = $db->fetch_row($result))
$old_searches[] = '\''.$db->escape($row[0]).'\'';
$db->query('DELETE FROM '.$db->prefix.'search_cache WHERE ident NOT IN('
.implode(',', $old_searches).')') or error('Unable to delete search results'
, __FILE__, __LINE__, $db->error());
}

.......... end ...........

 The 4th line of pasted code sets old_searches[] (array) to carefully validated 
data,

returned from database and then at next line it sends another query containing

old_searches[].

 If  "Global_register" of php.ini is set ON and there is no SQL injection 
filters ( or magic_quotes)

then poisoning old_searches can let remote users directly execute SQL commands.

Proof of Concepts:
--------------------
http://[site]/search.php?action=search&keywords=&author=d3vilbox&;
forum=-1&search_in=all&sort_by=0&sort_dir=DESC&show_as=topics
&search=Submit&old_searches[]=[sql injection]


Solution:
--------------------
find :
.......... Start ...........


if ($db->num_rows($result))
        {
while ($row = $db->fetch_row($result))
                
$old_searches[] = '\''.$db->escape($row[0]).'\'';
.......... End ...........

and add "$old_searches=array();" before beginning of "While" to clear 
old_searches.

it should looks like :

.......... Start ...........


$old_searches = array();
 

if ($db->num_rows($result))
        {
while ($row = $db->fetch_row($result))
                
$old_searches[] = '\''.$db->escape($row[0]).'\'';
.......... End ...........

More Detail:
--------------------
http://www.kapda.ir/advisory-91.html
Visit above link for more details.

Credit :
--------------------
Devil_box of KAPDA
devil_box [at}  kapda.ir
Kapda - Security Science Researchers Insitute of Iran
http://www.KAPDA.ir
(PersianHacker.NET)

Original Advisory : http://www.kapda.ir/advisory-91.html
Special thanks to : Trueend and Irannetjob