# Title: Composr CMS 10.0.30 - Persistent Cross-Site Scripting# Author: Manuel Garcia Cardenas# Date: 2020-02-06# Vendor: https://compo.sr/# CVE: N/A=============================================
MGC ALERT 2020-001- Original release date: February 06,2020- Last revised:May 21,2020- Discovered by: Manuel Garcia Cardenas
- Severity:4,8/10(CVSS Base Score)- CVE-ID: CVE-2020-8789=============================================
I. VULNERABILITY
-------------------------
Composr CMS 10.0.30-(Authenticated) Cross-Site Scripting
II. BACKGROUND
-------------------------
Composr CMS (or Composr)is a web application for creating websites. It is
a combination of a Web content management system and Online community
(Social Networking) software. Composr is licensed as free software and
primarily written in the PHP programming language.
III. DESCRIPTION
-------------------------
Has been detected a Persistent XSS vulnerability in Composr CMS, that
allows the execution of arbitrary HTML/script code to be executed in the
context of the victim user's browser.
IV. PROOF OF CONCEPT
-------------------------
Go to: Security -> Usergroups -> Edit Usergroup
Select one Usergroup (for example Guest)and edit the Name (parameter name)for example with Guests"><script>alert(1)</script>
The variable "name" it isnot sanitized, later,if some user visit the
"Zone editor" area, the XSS is executed,in the response you can view:<inputtype="hidden" name="label_for__access_1" value="Access for
Guests"><script>alert(1)</script>"/>
V. BUSINESS IMPACT
-------------------------
An attacker can execute arbitrary HTML or Javascript code in a targeted
user's browser, this can leverage to steal sensitive information as user
credentials, personal data, etc.
VI. SYSTEMS AFFECTED
-------------------------
Composr CMS<=10.0.30
VII. SOLUTION
-------------------------
Disable until a fix is available.
VIII. REFERENCES
-------------------------
https://compo.sr/
IX. CREDITS
-------------------------
This vulnerability has been discovered and reported
by Manuel Garcia Cardenas (advidsec (at) gmail (dot) com).
X. REVISION HISTORY
-------------------------
February 06,20201: Initial release
May 21,20202: Last revision
XI. DISCLOSURE TIMELINE
-------------------------
February 06,20201: Vulnerability acquired by Manuel Garcia Cardenas
February 06,20202: Send to vendor
April 06,20203: New request, vendor doesn't answer.
May 21,20204: Sent to lists
XII. LEGAL NOTICES
-------------------------
The information contained within this advisory is supplied "as-is"with no
warranties or guarantees of fitness of use or otherwise.
XIII. ABOUT
-------------------------
Manuel Garcia Cardenas
Pentester