CVE-2021-22950 in Concrete
Summary
by MITRE • 09/24/2021
Concrete CMS prior to 8.5.6 had a CSFR vulnerability allowing attachments to comments in the conversation section to be deleted.Credit for discovery: "Solar Security Research Team"
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Analysis
by VulDB Data Team • 10/02/2021
The vulnerability identified as CVE-2021-22950 affects Concrete CMS versions prior to 8.5.6, representing a cross-site request forgery flaw that specifically targets the conversation section of the platform. This issue was discovered and reported by the Solar Security Research Team, highlighting a critical weakness in the content management system's security architecture. The vulnerability manifests in the comment attachment handling mechanism, where unauthorized deletion of comment attachments can occur through crafted malicious requests.
Concrete CMS is a widely used open-source content management platform that allows users to create and manage digital content through a web-based interface. The conversation section within this platform enables users to engage in threaded discussions, often including file attachments to support their comments. The CSRF vulnerability exploited in this case allows attackers to manipulate the platform's functionality by tricking authenticated users into executing unintended actions without their knowledge or consent. This particular flaw specifically affects the attachment management capabilities within the conversation module, creating a scenario where malicious actors can remove comment attachments that users have uploaded.
The technical implementation of this vulnerability stems from insufficient validation of request origins and lack of proper anti-CSRF token mechanisms within the conversation section's attachment deletion endpoints. When users navigate to the conversation section and attempt to delete comment attachments, the system should verify that the request originates from the legitimate user interface rather than from a malicious third-party site. The absence of proper CSRF protection tokens or origin validation means that an attacker can construct a malicious web page that, when visited by an authenticated Concrete CMS user, automatically triggers the deletion of comment attachments. This type of vulnerability falls under CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in software applications.
The operational impact of this vulnerability extends beyond simple data loss, as it undermines the integrity and trustworthiness of user-generated content within the Concrete CMS platform. Comment attachments often contain valuable information, supporting documentation, or evidence that users have invested time and effort to create and share. The unauthorized deletion of these attachments can compromise ongoing discussions, destroy evidence of user interactions, and potentially impact business processes that rely on documented conversations. From an attacker's perspective, this vulnerability provides a method to disrupt user communications and potentially gain intelligence about user activities by removing evidence of specific discussions or interactions.
Organizations using Concrete CMS versions prior to 8.5.6 face significant risks when this vulnerability remains unpatched. The attack vector typically involves social engineering techniques where users are tricked into visiting malicious websites that contain embedded CSRF attack payloads. These attacks can be particularly effective in corporate environments where users may be more likely to visit external websites or where security awareness training may be insufficient. The vulnerability's impact is amplified in environments where comment attachments are frequently used for business-critical communications, project documentation, or customer support interactions.
Security mitigations for CVE-2021-22950 primarily involve upgrading to Concrete CMS version 8.5.6 or later, which includes proper CSRF protection mechanisms for the conversation section. Additionally, organizations should implement comprehensive security measures including input validation, proper token generation and validation, and regular security assessments of their CMS platforms. Network-level protections such as web application firewalls can provide additional layers of defense, though they cannot fully compensate for the underlying vulnerability. The ATT&CK framework categorizes this vulnerability under the T1566 technique for Social Engineering, specifically targeting the manipulation of user interactions through forged requests. Organizations should also consider implementing user education programs to raise awareness about the dangers of visiting untrusted websites and the importance of verifying website authenticity before engaging with content. Regular security audits and penetration testing of CMS platforms can help identify similar vulnerabilities before they can be exploited by malicious actors, ensuring that the platform maintains its integrity and protects user data effectively.