dotclear 2.8.1: Code Execution
Date: 2015-11-13 11:37:411. Introduction
| Affected Product: | dotclear 2.8.1 |
| Fixed in: | 2.8.2 |
| Fixed Version Link: | http://download.dotclear.org/latest.zip |
| Vendor Website: | http://dotclear.org/ |
| Vulnerability Type: | Code Execution |
| Remote Exploitable: | Yes |
| Reported to vendor: | 10/02/2015 |
| Disclosed to public: | 11/13/2015 |
| Release mode: | Coordinated release |
| CVE: | CVE-2015-8831 |
| Credits | Tim Coen of curesec GmbH |
2. Overview
CVSS
High 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C
Description
While upload of files with extension php, php4, and php5 is forbidden, upload of files with the extension pht, phps, and phtml is allowed, which will lead to code execution with most default Apache configurations.
The upload form is located here:
http://localhost/dotclear/admin/media.php?popup=1&plugin_id=dcLegacyEditor
A user with the right "manage their own media items" and "manage their own entries and comments" is needed to exploit this issue.
3. Code
/dotclear/inc/libs/clearbricks/filemanager
public function uploadFile($tmp,$dest,$overwrite=false)
{
$dest = $this->pwd.'/'.path::clean($dest);
if ($this->isFileExclude($dest)) {
throw new Exception(__('Uploading this file is not allowed.'));
}
[...]
if (@move_uploaded_file($tmp,$dest) === false) {
throw new Exception(__('An error occurred while writing the file.'));
}
[...]
}
[...]
protected function isFileExclude($f)
{
if (!$this->exclude_pattern) {
return false;
}
return preg_match($this->exclude_pattern,$f);
}
/dotclear/inc/core/class.dc.media.php
$this->exclude_pattern = $core->blog->settings->system->media_exclusion;
/dotclear/inc/core/class.dc.core.php
array('media_exclusion','string','/\.php[0-9]*$/i',
'File name exclusion pattern in media manager. (PCRE value)'),
Note that after installation, the regex is retrieved from the settings table of the database, not from the code.
4. Solution
To mitigate this issue please upgrade at least to version 2.8.2:
http://download.dotclear.org/latest.zip
Please note that a newer version might already be available.
5. Report Timeline
| 10/02/2015 | Informed Vendor |
| 10/25/2015 | Vendor releases fix |
| 11/13/2015 | Disclosed to public |