CVE-2021-4037 : Vulnerability Insights and Analysis
Learn about CVE-2021-4037, a Linux kernel vulnerability allowing local users to create files with unintended group ownership and excessive permissions on the XFS file-system. Find out about impact, affected versions, and mitigation strategies.
A vulnerability was found in the fs/inode.c:inode_init_owner() function logic of the LInux kernel that allows local users to create files with unintended group ownership and excessive permissions. This vulnerability is related to the XFS file-system.
Understanding CVE-2021-4037
This section will cover what CVE-2021-4037 is, its impact, technical details, and mitigation strategies.
What is CVE-2021-4037?
CVE-2021-4037 is a vulnerability in the Linux kernel that enables local users to create files with unintended group ownership and excessive permissions on the XFS file-system.
The Impact of CVE-2021-4037
The vulnerability can lead to scenarios where files have incorrect group ownership and permissions, potentially granting excessive access to unauthorized users.
Technical Details of CVE-2021-4037
This section will delve into the vulnerability description, affected systems, versions, and the exploitation mechanism.
Vulnerability Description
The flaw in the fs/inode.c:inode_init_owner() function logic allows non-group members to create files with unintended ownership and excessive permissions on XFS. This issue is reminiscent of CVE-2018-13405.
Affected Systems and Versions
The vulnerability affects the Linux kernel up to version v5.11-rc1. Users operating on the affected versions are at risk of unintended group ownership and excessive permissions.
Exploitation Mechanism
Exploitation requires a user without group membership to create files on an XFS file-system, leveraging the SGID permissions to gain unauthorized access.
Mitigation and Prevention
This section will cover immediate steps to take and long-term security practices to mitigate the risks posed by CVE-2021-4037.
Immediate Steps to Take
Users are advised to apply patches provided by the kernel maintainers promptly. Restricting directory permissions can also prevent unauthorized file creation.
Long-Term Security Practices
Regularly updating the Linux kernel and implementing access controls can enhance system security. Monitoring file permissions and ownership is crucial in preventing unauthorized access.
Patching and Updates
Stay informed about security advisories from trusted sources such as Red Hat and Debian to deploy patches in a timely manner.