SEC Consult Vulnerability Lab Security Advisory < 20200807-0 > ======================================================================= title: Multiple Vulnerabilities product: flatCore CMS vulnerable version: <=1.5.5 fixed version: 1.5.7 CVE number: - impact: High homepage: https://flatcore.org/ found: 2020-03-28 by: Farhan Rahman (Office Malaysia) Azrul Ikhwan Zulkifli (Office Malaysia) SEC Consult Vulnerability Lab An integrated part of SEC Consult Europe | Asia | North America https://www.sec-consult.com ======================================================================= Vendor description: ------------------- "flatCore is based on PHP and PDO/SQLite. The Core is as minimalistic as possible, but can be easily extended by the modular structure. If you are looking for a solution to edit your website live and with ease, flatCore may be your buddy." Source: https://flatcore.org/ Business recommendation: ------------------------ Update to the latest version of flatCore CMS. An in-depth security analysis performed by security professionals is highly advised, as the software may be affected from further security issues. Vulnerability overview/description: ----------------------------------- 1. Stored Cross Site Scripting (Authenticated user) This vulnerability allows an authenticated user (admin) to inject a malicious client side script which will be executed in the browser of a user if he visits the manipulated URL. In this case, the payload will be executed when the user visits any page that contains the injected malicious client side script. 2. Upload of arbitrary files (Authenticated user) It was identified that an authenticated user (admin) has the possibility to upload malicious files without any restriction. In this specific case, arbitrary server side PHP code such as web shells can be uploaded. As a result the attacker can run arbitrary code on the server side with the privileges of the web server. This could lead to a full system compromise. Proof of concept: ----------------- 1. Stored Cross Site Scripting (Authenticated user) The following parameters have been found to be vulnerable to stored cross site scripting attacks. (a) URL : http://$DOMAIN/acp/acp.php?tn=pages&sub=edit&editpage=1 METHOD : POST PARAMETER : page_linkname, page_title, page_content, page_extracontent PAYLOAD : aaaa%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E Go to http://$DOMAIN/ , and the XSS will be executed. (b) URL : http://$DOMAIN/acp/acp.php?tn=system&sub=sys_pref METHOD : POST PARAMETER : prefs_pagename, prefs_pagetitle, prefs_pagesubtitle PAYLOAD : aaaa%3Cscript%3Ealert%28document.cookie%29%3C%2Fscript%3E Go to http://$DOMAIN/ , and the XSS will be executed. 2. Upload of arbitrary files (Authenticated user) Go to Upload Files > Choose destination > files. Upload a desired PHP web shell as the shell.php file. Once uploaded, to execute the webshell, go to http://$DOMAIN/content/files/shell.php Vulnerable / tested versions: ----------------------------- flatCore CMS version 1.5.5 has been tested, which was the latest version available at the time of the test. Previous versions may also be affected. Vendor contact timeline: ------------------------ 2020-04-02: Contacting vendor through support@flatcore.org. 2020-04-28: Vendor developer asked for details. Sending details. 2020-06-02: Follow-up with vendor; no response. 2020-06-08: Follow-up with vendor; no response. 2020-06-10: Vendor requested to give them some times to patch the vulnerabilities. 2020-07-10: Follow-up with vendor; no response. 2020-07-22: Vendor fixed the reported issues, and release the new version (1.5.7) at their website. 2020-08-07: Public release of security advisory Solution: --------- The fixed version 1.5.7 is available at the vendor's download section: * https://flatcore.org/downloads/ Workaround: ----------- None Advisory URL: ------------- https://sec-consult.com/en/vulnerability-lab/advisories/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab SEC Consult Europe | Asia | North America About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://sec-consult.com/en/career/index.html Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://www.sec-consult.com/en/contact/index.html ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: research at sec-consult dot com Web: https://www.sec-consult.com Blog: http://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF F. Rahman, A. Zulkifli / @2020