Red Hat update for kernel

1) Security restrictions bypass

EUVDB-ID: #VU16558

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 - Permissions, Privileges, and Access Controls

Exploit availability: Yes

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

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.5

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.5

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.5

Red Hat Enterprise Linux Server - Extended Update Support: 7.5

kernel (Red Hat package): 3.10.0-123.1.2.el7 - 3.10.0-862.25.3.el7

Red Hat Enterprise Linux EUS Compute Node: 7.5

:

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian_-_extended_update_support:7.5:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_big_endian_-_extended_update_support:7.5:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems_-_extended_update_support:7.5:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red hat enterprise linux server - extended update support:7.5:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:kernel_redhat_package:3.10.0-514.73.1.el7:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:kernel_redhat_package:3.10.0-327.85.1.el7:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:kernel_redhat_package:3.10.0-693.64.1.el7:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_eus_compute_node:7.5:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:::::*:*:*:*:*:*:

External links

http://access.redhat.com/errata/RHSA-2019:0202

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.