4images 1.7.12 Cross Site Scripting

Type packetstorm
Reporter Tim Coen
Modified 2015-12-09T00:00:00


                                            `Security Advisory - Curesec Research Team  
1. Introduction  
Affected Product: 4images 1.7.12  
Fixed in: 1.7.13 (update)  
Fixed Version Link: http://www.4homepages.de/download-4images  
Vendor Website: http://www.4homepages.de/  
Vulnerability Type: XSS  
Remote Exploitable: Yes  
Reported to vendor: 09/29/2015  
Disclosed to public: 12/02/2015  
Release mode: Coordinated release  
CVE: Requested, but not assigned  
Credits Tim Coen of Curesec GmbH  
2. Overview  
There are two reflected XSS vulnerabilities in 4images, as well as a persistent  
Open Redirect, which may also lead to XSS in older browsers.  
This allows an attacker to execute arbitrary JavaScript in the context of the  
browser of a victim if the victim clicks on an attacker supplied link or visits  
an attacker controlled website. With this, it is possible to bypass CSRF  
protection and thus do anything the victim can do, inject a JavaScript  
keylogger, or perform phishing attacks.  
It should be noted that the XSS vulnerability still existed in another form in  
the first release of version 1.17.13 and has been fixed with an update to that  
3. Reflected XSS 1  
Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N  
When displaying the form to add new images, $_SERVER['PHP_SELF'] is echoed  
unencoded inside a select tag. Because of this, additional attributes can be  
added and new HTML tags can be created, leading to XSS.  
Proof of Concept  
Prior to Version 1.7.12:  
http://localhost/4images/admin/images.php/" onfocus=alert(1) autofocus foo="?action=addimages  
Version 1.7.13 (before update):  
This required a click of the victim to trigger, and a redirect will be  
performed after the execution of the injected code.  
show_num_select_row(" ", "num_newimages", $lang['num_addnewimages_desc']);  
function show_num_select_row($title, $option, $desc = "") {  
global $site_sess, $PHP_SELF, $action, $$option;  
echo "<tr class=\"".get_row_bg()."\">\n<td><p>".$title."</p></td>\n";  
echo "<td align=\"right\"><p>".$desc;  
$url = $PHP_SELF;  
$url .= preg_match("/\?/", $url) ? "&" : "?";  
$url .= "action=".$action;  
$url = $site_sess->url($url);  
echo "<select name=\"num\" onchange=\"window.location=('".$url."&";  
echo $option."='+this.options[this.selectedIndex].value)\">\n";  
for ($i = 1; $i < 11; $i++) {  
echo "<option value=\"$i\"";  
if ($i == ${$option}) {  
echo " selected";  
echo ">".$i."</option>\n";  
echo "</select></p></td>\n</tr>\n";  
4. Reflected XSS 2  
Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N  
User input is echoed inside the src attribute of a frame, which makes it  
possible to execute javascript.  
Proof of Concept  
if ($action == "") {  
$action = "frames";  
if ($action == "frames") {  
if ($goto != "" && strpos($goto, '://') === false) {  
$framesrc = $site_sess->url($goto);  
else {  
$framesrc = $site_sess->url("home.php");  
<html dir="<?php echo $lang['direction']; ?>">  
<title><?php echo $config['site_name']; ?> Control Panel</title>  
<meta http-equiv="Content-Type" content="text/html; charset=<?php echo $lang['charset']; ?>">  
<frameset rows="70,*" framespacing="0" border="0" frameborder="0" frameborder="no" border="0">  
<frame src="<?php echo $site_sess->url("index.php?action=head"); ?>" name="head" scrolling="NO" NORESIZE frameborder="0" marginwidth="0" marginheight="0" border="no">  
<frameset cols="216,*" framespacing="0" border="0" frameborder="0" frameborder="no" border="0">  
<frame src="<?php echo $site_sess->url("index.php?action=nav"); ?>" name="nav" scrolling="auto" NORESIZE frameborder="0" marginwidth="0" marginheight="0" border="no">  
<frame src="<?php echo $framesrc ?>" name="main" scrolling="auto" NORESIZE frameborder="0" marginwidth="20" marginheight="20" border="no">  
5. Persistent Open Redirect  
Medium 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N  
When showing an uploaded image, the description and keyword are not properly  
encoded. Tags are removed, but it is still possible to add further attributes  
to the meta tag they are inserted into.  
This makes it possible to inject a redirect. This redirect will be persistent,  
meaning anyone visiting the site of the uploaded image will be redirected to an  
attacker controlled website.  
The attacker needs the rights to upload images to perform the attack, which  
means that a category needs to exist where anyone can upload images, or a  
category needs to exist where registered users can upload images and the  
registration must be open - which it is by default.  
Proof of Concept  
Upload an image, as description or keyword use:  
Version 1.7.11 and earlier:  
5;URL=http://google.com/" http-equiv="refresh" foo="  
Version 1.7.12:  
5;URL=http://google.com/" http-equiv=refresh foo="  
When visiting the page of the uploaded image, a redirect will be performed.  
With older browsers, it will be possible to inject and execute javascript as  
$meta_keywords = !empty($image_row['image_keywords']) ? strip_tags(implode(", ", explode(",", $image_row['image_keywords']))) : "";  
$meta_description = !empty($image_row['image_description']) ? strip_tags($image_row['image_description']) . ". " : "";  
"detail_meta_description" => $meta_description,  
"detail_meta_keywords" => $meta_keywords,  
"prepend_head_title" => $image_name . " - ",  
6. Solution  
To mitigate this issue please upgrade at least to version 1.7.13:  
Please note that a newer version might already be available.  
7. Report Timeline  
09/29/2015 Informed Vendor about Issue  
10/21/2015 Reminded Vendor of Disclosure Date  
11/03/2015 Vendor releases new version (1.7.12), partially fixing issues  
11/17/2015 CVE Requested (no reply)  
11/18/2015 Vendor releases new version (1.7.13), partially fixing issues  
11/23/2015 Vendor releases update to version 1.7.13, fixing the issues  
12/02/2015 Disclosed to public  
Blog Reference:  
blog: https://blog.curesec.com  
tweet: https://twitter.com/curesec  
Curesec GmbH  
Curesec Research Team  
Romain-Rolland-Str 14-24  
13089 Berlin, Germany