CVE-2019-19448 : Security Advisory and Response
Learn about CVE-2019-19448, a critical use-after-free vulnerability in Linux kernel versions 5.0.21 and 5.3.11. Find out the impact, affected systems, exploitation details, and mitigation steps.
A use-after-free vulnerability in the Linux kernel versions 5.0.21 and 5.3.11 can be exploited when specific actions are performed on a mounted btrfs filesystem image, followed by a syncfs system call.
Understanding CVE-2019-19448
This CVE involves a critical vulnerability in the Linux kernel that can lead to a use-after-free condition.
What is CVE-2019-19448?
A use-after-free vulnerability occurs in the Linux kernel versions 5.0.21 and 5.3.11 when a btrfs filesystem image is mounted, specific actions are taken, and a syncfs system call is made. The vulnerability arises due to a pointer issue within the try_merge_free_space function in fs/btrfs/free-space-cache.c.
The Impact of CVE-2019-19448
This vulnerability could allow an attacker to execute arbitrary code or cause a denial of service (DoS) condition on the affected system, potentially leading to system compromise or data loss.
Technical Details of CVE-2019-19448
This section provides more in-depth technical details about the vulnerability.
Vulnerability Description
The vulnerability is caused by the possibility of having the pointer to a left data structure being equal to the pointer to a right data structure within the try_merge_free_space function in fs/btrfs/free-space-cache.c.
Affected Systems and Versions
- Linux kernel versions 5.0.21 and 5.3.11
Exploitation Mechanism
- Mounting a crafted btrfs filesystem image
- Performing specific operations
- Making a syncfs system call
Mitigation and Prevention
Protecting systems from CVE-2019-19448 requires immediate actions and long-term security practices.
Immediate Steps to Take
- Apply security updates provided by the Linux distribution vendors
- Monitor vendor advisories for patches and mitigations
- Implement least privilege access controls
Long-Term Security Practices
- Regularly update and patch the Linux kernel
- Conduct security assessments and audits of the system
- Employ intrusion detection and prevention systems
Patching and Updates
- Stay informed about security updates from Linux distribution vendors
- Apply patches promptly to address known vulnerabilities