Vulnerability identifier: #VU16558

Vulnerability risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C]

CVE-ID: CVE-2018-18397

CWE-ID: CWE-264

Exploitation vector: Local

Exploit availability: Yes

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local attacker to bypass security restrictions on the target system.

The vulnerability exists due to improper access control in the userfaultfd implementation. A local attacker can access a system that is mounted with shmem or hugetlbs virtual memory areas, maliciously modify mapping to targeted files and write arbitrary memory on the system, which could be used to conduct additional attacks.

Mitigation
The vulnerability has been addressed in the versions 4.14.87, 4.19.8.

Vulnerable software versions

Linux kernel: 4.11 - 4.11.12, 4.12 - 4.12.14, 4.13 - 4.13.16, 4.14.0 - 4.14.89, 4.15.0 - 4.15.18, 4.16 - 4.16.18, 4.17 - 4.17.19, 4.18 - 4.18.20, 4.19 - 4.19.10, 4.20 rc5

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External links
http://github.com/torvalds/linux/commit/29ec90660d68bbdd69507c1c8b4e33aa299278b1

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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.