CVE-2021-41864 : Exploit Details and Defense Strategies
Learn about CVE-2021-41864, a critical Linux kernel vulnerability prealloc_elems_and_freelist in kernel/bpf/stackmap.c allowing unprivileged users an integer overflow exploit with out-of-bounds write.
The CVE-2021-41864 vulnerability in the Linux kernel before version 5.14.12 allows unprivileged users to trigger an eBPF multiplication integer overflow with an out-of-bounds write.
Understanding CVE-2021-41864
This CVE affects the kernel's prealloc_elems_and_freelist functionality in kernel/bpf/stackmap.c.
What is CVE-2021-41864?
The vulnerability permits unprivileged users to exploit an eBPF multiplication integer overflow, leading to an out-of-bounds write scenario.
The Impact of CVE-2021-41864
The vulnerability enables attackers to execute malicious code or potentially crash the system, posing a significant security risk to affected systems.
Technical Details of CVE-2021-41864
CVE-2021-41864 details the following technical aspects:
Vulnerability Description
- The flaw is in prealloc_elems_and_freelist in kernel/bpf/stackmap.c
Affected Systems and Versions
- Linux kernel versions prior to 5.14.12
Exploitation Mechanism
- Unprivileged users can exploit an eBPF multiplication integer overflow, resulting in an out-of-bounds write.
Mitigation and Prevention
Steps to mitigate the CVE-2021-41864 vulnerability:
Immediate Steps to Take
- Update the Linux kernel to version 5.14.12 or later
- Monitor system logs for any unusual activities
- Implement the principle of least privilege to limit user access
Long-Term Security Practices
- Regularly apply security patches and updates
- Conduct security training for staff on identifying and reporting vulnerabilities
Patching and Updates
- Patch the system with the latest Linux kernel updates to address the vulnerability