CVE-2019-20812 : Vulnerability Insights and Analysis
Learn about CVE-2019-20812, a Linux kernel vulnerability before 5.4.7 causing denial of service due to excessive CPU usage and system freeze. Find mitigation steps here.
A problem has been found in the Linux kernel versions prior to 5.4.7. The function prb_calc_retire_blk_tmo() in net/packet/af_packet.c may cause a denial of service (excessive CPU usage and system freeze) in a specific scenario related to TPACKET_V3, also known as CID-b43d1f9f7067.
Understanding CVE-2019-20812
An issue was discovered in the Linux kernel before 5.4.7. The prb_calc_retire_blk_tmo() function in net/packet/af_packet.c can result in a denial of service (CPU consumption and soft lockup) in a certain failure case involving TPACKET_V3, aka CID-b43d1f9f7067.
What is CVE-2019-20812?
CVE-2019-20812 is a vulnerability found in the Linux kernel versions prior to 5.4.7 that can lead to a denial of service due to excessive CPU usage and system freeze in a specific scenario related to TPACKET_V3.
The Impact of CVE-2019-20812
The vulnerability can be exploited to cause a denial of service, resulting in excessive CPU consumption and system freeze, affecting the availability and performance of the system.
Technical Details of CVE-2019-20812
The following technical details provide insight into the vulnerability.
Vulnerability Description
The prb_calc_retire_blk_tmo() function in net/packet/af_packet.c within the Linux kernel versions prior to 5.4.7 is susceptible to a denial of service attack, leading to excessive CPU usage and system freeze.
Affected Systems and Versions
- Linux kernel versions prior to 5.4.7
Exploitation Mechanism
The vulnerability can be exploited in a specific scenario related to TPACKET_V3, also known as CID-b43d1f9f7067, resulting in a denial of service due to excessive CPU consumption and system freeze.
Mitigation and Prevention
To address CVE-2019-20812, the following mitigation strategies can be implemented:
Immediate Steps to Take
- Update the Linux kernel to version 5.4.7 or later to mitigate the vulnerability.
- Monitor system performance for any signs of excessive CPU usage or system freeze.
Long-Term Security Practices
- Regularly update the Linux kernel and other software components to patch known vulnerabilities.
- Implement network segmentation and access controls to reduce the attack surface.
Patching and Updates
- Apply patches provided by the Linux kernel maintainers to address the vulnerability and enhance system security.