CVE-2021-22949 in Concrete
Summary
by MITRE • 09/24/2021
A CSRF in Concrete CMS version 8.5.5 and below allows an attacker to duplicate files which can lead to UI inconvenience, and exhaustion of disk space.Credit for discovery: "Solar Security CMS Research Team"
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Analysis
by VulDB Data Team • 10/02/2021
The vulnerability identified as CVE-2021-22949 represents a cross-site request forgery flaw within Concrete CMS version 8.5.5 and earlier releases. This security weakness resides in the application's failure to properly validate and authenticate file duplication requests, creating an avenue for malicious actors to exploit the system's file management functionality. The Concrete CMS platform, widely used for content management and website development, becomes susceptible to unauthorized file operations when this vulnerability is leveraged by attackers. The issue stems from the absence of proper anti-CSRF tokens or validation mechanisms during file duplication processes, allowing remote attackers to craft malicious requests that appear legitimate to the system.
The technical implementation of this vulnerability enables attackers to perform unauthorized file duplication operations within the CMS environment. When a user interacts with the CMS interface and subsequently visits a malicious website or clicks on a compromised link, the attacker can trigger file duplication requests without the user's knowledge or consent. This occurs because the application does not adequately verify the origin of file duplication requests, nor does it implement sufficient session validation controls. The flaw operates at the web application level, specifically within the file management module where users typically have permissions to duplicate files for content organization purposes. The vulnerability allows for repeated file duplication operations that can rapidly consume available disk space, creating both operational disruption and potential denial of service conditions.
The operational impact of this CSRF vulnerability extends beyond simple UI inconvenience to encompass significant resource exhaustion concerns. Attackers can systematically duplicate files across multiple directories, leading to rapid disk space consumption that may eventually render the CMS platform unusable. This resource exhaustion can cause cascading failures throughout the website infrastructure, affecting not only content management capabilities but potentially disrupting other services that depend on the underlying file system. The vulnerability's exploitation can result in increased storage costs, system downtime, and potential data loss scenarios. Additionally, the cumulative effect of multiple file duplications can cause performance degradation, making legitimate user operations slow or impossible. The impact is particularly severe in environments where storage capacity is limited or where automated backup processes are affected by disk space exhaustion.
Mitigation strategies for CVE-2021-22949 should prioritize immediate application updates to versions that address the CSRF validation issues. Organizations must ensure that all Concrete CMS installations are upgraded to versions 8.5.6 or later, where proper anti-CSRF token implementations have been integrated into the file duplication functionality. Network administrators should implement additional security controls including web application firewalls that can detect and block suspicious file duplication patterns. The implementation of proper session management controls and CSRF token validation mechanisms should be enforced throughout the application's file handling processes. Security teams should also consider implementing automated monitoring systems that can detect unusual file duplication activities and alert administrators to potential exploitation attempts. According to CWE standards, this vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery issues, and follows ATT&CK framework tactics related to privilege escalation and resource exhaustion through malicious file operations. Organizations should also conduct comprehensive security assessments to identify any other potential CSRF vulnerabilities within their CMS environments and ensure that all user interactions with file management features are properly authenticated and validated.