dotclear 2.8.1 Shell Upload

`Security Advisory - Curesec Research Team  
  
1. 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: n/a  
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  
  
  
Blog Reference:  
http://blog.curesec.com/article/blog/dotclear-281-Code-Execution-93.html  
  
  
`