Ubuntu update for linux

Published: 2022-01-06

Risk	Low
Patch available	YES
Number of vulnerabilities	6
CVE-ID	CVE-2021-20317 CVE-2021-20321 CVE-2021-3760 CVE-2021-4002 CVE-2021-41864 CVE-2021-43389
CWE-ID	CWE-665 CWE-362 CWE-416 CWE-401 CWE-787 CWE-129
Exploitation vector	Local
Public exploit	N/A
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gcp (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gke (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-azure (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oem (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-virtual-hwe-16.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-lowlatency-hwe-16.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic-hwe-16.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-azure-lts-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1129-azure (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-virtual (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-snapdragon (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-raspi2 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oracle-lts-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-kvm (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gcp-lts-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-dell300x (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-aws-lts-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-166-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-166-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-166-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1118-snapdragon (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1118-aws (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1114-gcp (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1105-kvm (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1101-raspi2 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1085-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1033-dell300x (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-aws-hwe (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 6 vulnerabilities.

1) Improper Initialization

EUVDB-ID: #VU58208

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-20317

CWE-ID: CWE-665 - Improper Initialization

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to improper initialization the Linux kernel. A corrupted timer tree causes the task wakeup to be missing in the timerqueue_add function in lib/timerqueue.c. A local user can run a specially crafted application to crash the kernel.

Mitigation

Update the affected package linux to the latest version.

Vulnerable software versions

Ubuntu: 14.04 - 18.04

linux-image-oracle (Ubuntu package): before 5.11.0.1022.23~20.04.15

linux-image-gcp (Ubuntu package): before 5.11.0.1023.25~20.04.22

linux-image-gke (Ubuntu package): before 5.11.0.1023.23

linux-image-azure (Ubuntu package): before 5.11.0.1022.23~20.04.22

linux-image-oem (Ubuntu package): before 5.4.0.91.95

linux-image-virtual-hwe-16.04 (Ubuntu package): before 4.15.0.187.173

linux-image-lowlatency-hwe-16.04 (Ubuntu package): before 4.15.0.187.173

linux-image-generic-hwe-16.04 (Ubuntu package): before 4.15.0.187.173

linux-image-azure-lts-18.04 (Ubuntu package): before 4.15.0.1129.102

linux-image-4.15.0-1129-azure (Ubuntu package): before 4.15.0-1129.142

linux-image-virtual (Ubuntu package): before 4.15.0.166.155

linux-image-snapdragon (Ubuntu package): before 4.15.0.1118.121

linux-image-raspi2 (Ubuntu package): before 4.15.0.1101.99

linux-image-oracle-lts-18.04 (Ubuntu package): before 4.15.0.1085.95

linux-image-lowlatency (Ubuntu package): before 4.15.0.166.155

linux-image-kvm (Ubuntu package): before 4.15.0.1105.101

linux-image-generic-lpae (Ubuntu package): before 4.15.0.166.155

linux-image-generic (Ubuntu package): before 4.15.0.166.155

linux-image-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1114.133

linux-image-dell300x (Ubuntu package): before 4.15.0.1033.35

linux-image-aws-lts-18.04 (Ubuntu package): before 4.15.0.1118.121

linux-image-4.15.0-166-lowlatency (Ubuntu package): before 4.15.0-166.174

linux-image-4.15.0-166-generic-lpae (Ubuntu package): before 4.15.0-166.174

linux-image-4.15.0-166-generic (Ubuntu package): before 4.15.0-166.174

linux-image-4.15.0-1118-snapdragon (Ubuntu package): before 4.15.0-1118.127

linux-image-4.15.0-1118-aws (Ubuntu package): before 4.15.0-1118.125

linux-image-4.15.0-1114-gcp (Ubuntu package): before 4.15.0-1114.128

linux-image-4.15.0-1105-kvm (Ubuntu package): before 4.15.0-1105.107

linux-image-4.15.0-1101-raspi2 (Ubuntu package): before 4.15.0-1101.108

linux-image-4.15.0-1085-oracle (Ubuntu package): before 4.15.0-1085.93

linux-image-4.15.0-1033-dell300x (Ubuntu package): before 4.15.0-1033.38

linux-image-aws-hwe (Ubuntu package): before 4.15.0.1099.92

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5209-1

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.

2) Race condition

EUVDB-ID: #VU59084

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-20321

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service (DoS) attacks.

The vulnerability exists due to a race condition when accessing file object in the Linux kernel OverlayFS subsystem. A local user can rename files in specific way with OverlayFS and perform a denial of service (DoS) attack.