Red Hat Enterprise Linux 8.1 Extended Update Support update for kernel

1) Use-after-free

EUVDB-ID: #VU58332

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-36385

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

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

The vulnerability exists due to a use-after-free error in drivers/infiniband/core/ucma.c, because the ctx is reached via the ctx_list in some ucma_migrate_id situations where ucma_close is called. A local user can run a specially crafted program to trigger the use-after-free error and execute arbitrary code with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support: 8.1

Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support: 8.1

Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support: 8.1

Red Hat Enterprise Linux for ARM 64 - Extended Update Support: 8.1

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 8.1

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 8.1

Red Hat Enterprise Linux for x86_64 - Extended Update Support: 8.1

kernel (Red Hat package): before 4.18.0-147.57.1.el8_1

CPE2.3

• cpe:2.3:o:red_hat:red hat codeready linux builder for arm 64 - extended update support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red hat codeready linux builder for power, little endian - extended update support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red hat codeready linux builder for x86_64 - extended update support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_x86_64_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:

External links

http://access.redhat.com/errata/RHSA-2021:4687

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.