CVE-2019-5606 Explained : Impact and Mitigation
Learn about CVE-2019-5606, a FreeBSD vulnerability allowing unauthorized users to gain root privileges. Find mitigation steps and system update recommendations here.
In versions of FreeBSD 12.0-STABLE before r349805, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r349806, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, a vulnerability exists in the code responsible for closing a descriptor created by posix_openpt. This flaw can lead to a write after free vulnerability in the kernel memory, potentially allowing unauthorized users to gain root privileges or escape a jail.
Understanding CVE-2019-5606
This CVE involves a kernel use after free vulnerability in FreeBSD.
What is CVE-2019-5606?
CVE-2019-5606 is a vulnerability in FreeBSD versions before specific releases, where a flaw in handling descriptor closure can result in a write after free vulnerability in kernel memory.
The Impact of CVE-2019-5606
The vulnerability can be exploited by unauthorized users to potentially gain root privileges or escape a jail environment.
Technical Details of CVE-2019-5606
This section provides detailed technical information about the vulnerability.
Vulnerability Description
The issue arises from the failure to revert a signal configuration when closing a descriptor, leading to an incorrect signal being raised and resulting in a write after free vulnerability in kernel memory.
Affected Systems and Versions
- FreeBSD versions before 12.0-RELEASE-p8
- FreeBSD versions before 11.3-RELEASE-p1
- FreeBSD versions before 11.2-RELEASE-p12
Exploitation Mechanism
The vulnerability can be exploited by manipulating the signal configuration during the closure of a descriptor, allowing unauthorized users to gain elevated privileges.
Mitigation and Prevention
Protective measures and actions to mitigate the impact of CVE-2019-5606.
Immediate Steps to Take
- Apply the necessary patches provided by FreeBSD to address the vulnerability.
- Monitor system logs for any suspicious activities that may indicate exploitation of the vulnerability.
Long-Term Security Practices
- Regularly update FreeBSD systems to the latest stable releases to ensure all security patches are applied.
- Implement least privilege access controls to limit the capabilities of potential attackers.
Patching and Updates
- Ensure timely installation of security updates and patches released by FreeBSD to address CVE-2019-5606.