Security Advisory - Curesec Research Team

1. Introduction

Affected Product:    Chyrp CMS 2.5.2
Fixed in:            not fixed
Fixed Version Link:  n/a
Vendor Github:       https://github.com/chyrp/chyrp
Vulnerability Type:  XSS
Remote Exploitable:  Yes
Reported to vendor:  09/01/2015
Disclosed to public: 10/07/2015
Release mode:        Full Disclosure
CVE:                 n/a
Credits              Tim Coen of Curesec GmbH

2. Vulnerability Description

There is an XSS vulnerability in Chyrp CMS 2.5.2. With this, it is possible to
steal cookies, bypass CSRF protection, or inject JavaScript keyloggers.

The vulnerability exists because the key of all GET arguments is echoed without
encoding.

3. Proof of Concept


http://localhost/chyrp/themes/firecrest/images/dots-green.gif?"></script><script>alert(1)</script>=1

4. Code


        /includes/class/Theme.php:231
                public function javascripts() {
                    $config = Config::current();
                    $route = Route::current();

                    $args = "";
                    foreach ($_GET as $key => $val)
                        if (!empty($val) and $val != $route->action)
                            $args.= "&".$key."=".urlencode($val);

                    $javascripts = array($config->chyrp_url."/includes/lib/gz.php?file=jquery.js",
                                         $config->chyrp_url."/includes/lib/gz.php?file=plugins.js",
                                         $config->chyrp_url.'/includes/javascript.php?action='.$route->action.$args);

5. Solution

This issue was not fixed by the vendor.

6. Report Timeline

09/01/2015 Informed Vendor about Issue (no reply)
09/22/2015 Reminded Vendor of disclosure date (no reply)
10/07/2015 Disclosed to public


Blog Reference:
http://blog.curesec.com/article/blog/Chyrp-CMS-252-XSS-61.html