Privilege escalation in Linux kernel io_uring

1) Improper Privilege Management

EUVDB-ID: #VU68300

Risk: Low

CVSSv3.1: 7 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-41073

CWE-ID: CWE-269 - Improper Privilege Management

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper privilege management within the loop_rw_iter() function in fs/io_uring.c in Linux kernel. A local user can escalate privileges on the system by using IORING_OP_PROVIDE_BUFFERS to trigger a free of a kernel buffer.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Linux kernel: All versions

CPE2.3

External links

http://www.openwall.com/lists/oss-security/2021/09/18/2
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=16c8d2df7ec0eed31b7d3b61cb13206a7fb930cc
http://www.debian.org/security/2021/dsa-4978
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PAP4TXEZ7J4EZQMQW5SIJMWXG7WZT3F7/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/J7KSMIOQ4377CVTHMWNGNCWHMCRFRP2T/
http://security.netapp.com/advisory/ntap-20211014-0003/
http://www.openwall.com/lists/oss-security/2022/06/04/4

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. However, proof of concept for this vulnerability is available.