CVE-2019-19039 : Exploit Details and Defense Strategies
Learn about CVE-2019-19039, a vulnerability in the Linux kernel allowing local users to access sensitive register values via the dmesg program. Find mitigation steps and prevention measures here.
According to the BTRFS development team, the function __btrfs_free_extent in the file fs/btrfs/extent-tree.c in the Linux kernel up to version 5.3.12 invokes btrfs_print_leaf in a specific scenario where ENOENT is encountered. This behavior could potentially allow local users to access confidential information about register values through the dmesg program. The issue is disputed by the BTRFS team, citing kernel features that enable system administrators to restrict dmesg access.
Understanding CVE-2019-19039
This CVE involves a potential information disclosure vulnerability in the Linux kernel.
What is CVE-2019-19039?
The CVE-2019-19039 vulnerability in the Linux kernel allows local users to obtain sensitive information about register values via the dmesg program.
The Impact of CVE-2019-19039
The vulnerability could lead to unauthorized access to confidential information by local users through the dmesg program.
Technical Details of CVE-2019-19039
This section provides detailed technical information about the vulnerability.
Vulnerability Description
The function __btrfs_free_extent in fs/btrfs/extent-tree.c in the Linux kernel through version 5.3.12 calls btrfs_print_leaf in a specific ENOENT case, potentially exposing sensitive register values.
Affected Systems and Versions
- Affected System: Linux kernel up to version 5.3.12
- Affected Component: fs/btrfs/extent-tree.c
Exploitation Mechanism
Local users can exploit this vulnerability to access confidential information about register values through the dmesg program.
Mitigation and Prevention
Protecting systems from CVE-2019-19039 requires immediate actions and long-term security practices.
Immediate Steps to Take
- System administrators should consider restricting dmesg access using the dmesg_restrict=1 sysctl option.
Long-Term Security Practices
- Regularly review and update kernel security configurations.
- Implement least privilege access controls to limit user capabilities.
Patching and Updates
- Apply security updates provided by the Linux kernel maintainers.