Privilege escalation in Linux kernel ebpf

1) Race condition

EUVDB-ID: #VU81665

Risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-4001

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in kernel/bpf/syscall.c in Linux kernel ebpf. A local user can exploit the race between bpf_map_update_elem and bpf_map_freeze and modify the frozen mapped address space.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: before

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:*:*:*:*:*:*:*:*

External links

https://bugzilla.redhat.com/show_bug.cgi?id=2025645
https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=353050be4c19e102178ccc05988101887c25ae53

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.