CVE-2021-36539 : Exploit Details and Defense Strategies
Learn about CVE-2021-36539, a vulnerability in Instructure Canvas LMS allowing unprivileged users to access locked/unpublished files via a specific URL. Find mitigation steps here.
A security vulnerability in Instructure Canvas LMS could allow unprivileged users to access locked/unpublished files via a specific URL.
Understanding CVE-2021-36539
This section provides insights into the impact, technical details, and mitigation strategies related to CVE-2021-36539.
What is CVE-2021-36539?
The CVE-2021-36539 vulnerability in Instructure Canvas LMS allows unauthorized access to locked or unpublished files through a specific URL, potentially exposing sensitive information to unprivileged users.
The Impact of CVE-2021-36539
The impact of this vulnerability is significant as it compromises the confidentiality of files that were meant to be restricted. Unprivileged users can view sensitive documents, leading to a breach of data privacy and security.
Technical Details of CVE-2021-36539
This section delves into the specifics of the vulnerability, affected systems, and how it can be exploited.
Vulnerability Description
Instructure Canvas LMS fails to properly restrict access to locked/unpublished files through the DocViewer based file preview URL, known as canvadoc_session_url, enabling unauthorized users to view the contents.
Affected Systems and Versions
The vulnerability impacts all versions of Instructure Canvas LMS, allowing unprivileged users to bypass file access restrictions and view confidential information.
Exploitation Mechanism
By accessing the specific URL (canvadoc_session_url), unprivileged users can exploit the vulnerability to view locked or unpublished files within the Instructure Canvas LMS platform.
Mitigation and Prevention
Discover the necessary steps to address and prevent the exploitation of CVE-2021-36539.
Immediate Steps to Take
It is crucial to restrict access to the vulnerable URL and monitor file access to detect any unauthorized attempts. Administrators should also review file permissions and user roles to ensure proper access control.
Long-Term Security Practices
Implement regular security audits and penetration testing to identify and remediate vulnerabilities proactively. Consider educating users on data privacy best practices and the importance of maintaining access controls.
Patching and Updates
Stay informed about security patches released by Instructure for Canvas LMS and promptly apply them to mitigate the CVE-2021-36539 vulnerability.