XSS vulnerability

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Oliver Georgi
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Joined: Fri 3. Oct 2003, 22:22
Location: Moscow, Russia

XSS vulnerability

Post by Oliver Georgi »

Yesterday I got report of an existing XSS vulnerability.
http://www.htbridge.ch/advisory/xss_vul ... pwcms.html

It seems to have an effect only when you are logged in to the backend. If you do not use the calendar module of phpwcms, just delete folder

The fix for this is change starting around line 42 to:
For all releases this is enough:

Code: Select all

// Change:
$_SESSION['calendardate'] = clean_slweg($_GET['calendardate']);
// To:
$_SESSION['calendardate'] = substr(clean_slweg($_GET['calendardate']), 0, 7);
For newer releases use

Code: Select all

// define some defaults
if(isset($_GET['calendardate'])) {

	$_SESSION['calendardate'] = substr(clean_slweg($_GET['calendardate']), 0, 7);

if(!empty($_SESSION['calendardate'])) {

	@list($plugin['current_month'], $plugin['current_year']) = explode('-', $_SESSION['calendardate']);
	$plugin['current_month']	= intval($plugin['current_month']);
	$plugin['current_year']		= intval($plugin['current_year']);
	if(empty($plugin['current_year'])) {
		$plugin['current_year']		= gmdate('Y');
	if(empty($plugin['current_month'])) {
		$plugin['current_month']		= gmdate('n');

} else {

	$plugin['current_year']		= gmdate('Y');
	$plugin['current_month']	= gmdate('n');

Or use the attached file
replace the file include/inc_module/mod_calendar/backend.listing.php with unarchived version — make backup of old file and test it
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Last edited by Oliver Georgi on Wed 30. Sep 2015, 05:59, edited 4 times in total.
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