An issue was discovered in GetSimple CMS through 3.3.15. insufficient input sanitation in the theme-edit.php file allows upload of files with arbitrary content (PHP code, for example). This vulnerability is triggered by an authenticated user; however, authentication can be bypassed. According to the official documentation for installation step 10, an admin is required to upload all the files, including the .htaccess files, and run a health check. However, what is overlooked is that the Apache HTTP Server by default no longer enables the AllowOverride directive, leading to data/users/admin.xml password exposure. The passwords are hashed but this can be bypassed by starting with the data/other/authorization.xml API key. This allows one to target the session state, since they decided to roll their own implementation. The cookiename is crafted information that can be leaked from the frontend (site name and version). If a someone leaks the API key and the admin username, then they can bypass authentication. To do so, they need to supply a cookie based on an SHA-1 computation of this known information. The vulnerability exists in the admin/theme-edit.php file. This file checks for forms submissions via POST requests, and for the csrf nonce. If the nonce sent is correct, then the file provided by the user is uploaded. There is a path traversal allowing write access outside the jailed themes directory root. Exploiting the traversal is not necessary because the .htaccess file is ignored. A contributing factor is that there isn't another check on the extension before saving the file, with the assumption that the parameter content is safe. This allows the creation of web accessible and executable files with arbitrary content.
GetSimpleCMS-3.3.15 is affected by directory traversal. Remote attackers are able to delete arbitrary files via /GetSimpleCMS-3.3.15/admin/log.php
Cross Site Scripting (XSS) vulnerability in GetSimpleCMS <= 3.3.15 in admin/changedata.php via the redirecturl parameter and the headerssent function.
GetSimpleCMS <=3.3.15 has an open redirect in admin/changedata.php via the redirect function to the url parameter.
Cross Site Scriptiong (XSS) vulnerability in GetSimpleCMS <=3.3.15 via the timezone parameter to settings.php.
Cross Site Scripting vulnerability in GetSimpleCMS <=3.3.15 via the (1) sitename, (2) username, and (3) email parameters to /admin/setup.php
GetSimple CMS v3.3.15 has Persistent Cross-Site Scripting (XSS) in admin/theme-edit.php.
An issue was discovered in GetSimple CMS 3.3.15. An administrator can insert stored XSS via the admin/settings.php Custom Permalink Structure parameter, which injects the XSS payload into any page created at the admin/pages.php URI.
Cross Site Scripting vulnerability in GetSimpleCMS 3.3.16 in admin/upload.php by adding comments or jpg and other file header information to the content of xla, pages, and gzip files,
In GetSimpleCMS 3.3.15, admin/upload.php blocks .html uploads but Internet Explorer render HTML elements in a .eml file, because of admin/upload-uploadify.php, and validatesafefile in admin/inc/securityfunctions.php.