Privilege escalation in Linux Kernel

1) Privilege escalation

EUVDB-ID: #VU8828

Risk: Low

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-5123

CWE-ID: CWE-391 - Unchecked Error Condition

Exploit availability: Yes

Description

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

The waitid implementation in kernel/exit.c in the Linux kernel through 4.13.4 does not check that the incoming argument points to the userspace. This can allow local users to write directly to kernel memory, which could lead to privilege escalation.

Mitigation

Install update from vendor's repository.

Vulnerable software versions

Linux kernel: 4.13 - 4.13.4

External links

http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.7
http://access.redhat.com/security/cve/cve-2017-5123
http://seclists.org/oss-sec/2017/q4/78

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.