CVE-2021-40108 : Security Advisory and Response

Concrete CMS through 8.5.5 is vulnerable to CSRF in the Calendar feature due to the lack of ccm_token verification on a specific endpoint.

Understanding CVE-2021-40108

Concrete CMS has a security vulnerability that allows Cross-Site Request Forgery (CSRF) attacks in the Calendar feature, exposing users to potential exploitation.

What is CVE-2021-40108?

The issue in Concrete CMS through version 8.5.5 exposes a vulnerability where the ccm_token is not validated on the ccm/calendar/dialogs/event/add/save endpoint, making it susceptible to CSRF attacks.

The Impact of CVE-2021-40108

This vulnerability can be exploited by attackers to perform unauthorized actions on behalf of authenticated users, leading to data manipulation, unauthorized access, and potential security breaches.

Technical Details of CVE-2021-40108

Concrete CMS through 8.5.5 has the following technical details:

Vulnerability Description

The Calendar in Concrete CMS lacks proper ccm_token verification on the ccm/calendar/dialogs/event/add/save endpoint, enabling CSRF attacks.

Affected Systems and Versions

Product: Concrete CMS
Vendor: Concrete CMS
Versions Affected: up to version 8.5.5

Exploitation Mechanism

Attackers can create malicious requests containing crafted ccm_token values to execute unauthorized actions through the vulnerable Calendar feature.

Mitigation and Prevention

It is crucial to take immediate action to mitigate the risks associated with CVE-2021-40108:

Immediate Steps to Take

Implement a security patch provided by Concrete CMS to address the CSRF vulnerability.
Regularly monitor and review Calendar-related activities for suspicious behavior.

Long-Term Security Practices

Educate users on recognizing and avoiding phishing attempts that could lead to CSRF attacks.
Employ security tools and practices to detect and prevent CSRF vulnerabilities in web applications.

Patching and Updates

Stay informed about security updates and patches released by Concrete CMS to address known vulnerabilities.
Promptly apply updates to ensure the mitigation of security risks associated with CSRF attacks.