Ubuntu update for linux

Published: 2021-09-28

Risk	Medium
Patch available	YES
Number of vulnerabilities	5
CVE-ID	CVE-2021-33624 CVE-2021-3679 CVE-2021-37576 CVE-2021-38199 CVE-2021-38204
CWE-ID	CWE-843 CWE-400 CWE-787 CWE-362 CWE-416
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-gkeop (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gcp-lts-20.04 (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-5.4.0-1053-gcp (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gke-5.4 (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-gke (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oracle-lts-20.04 (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-5.4.0-1047-kvm (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-1055-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-aws-lts-20.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-1024-gkeop (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-1059-azure (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-gkeop-5.4 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-1053-gke (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-88-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-azure-lts-20.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-1057-aws (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oem-osp1 (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-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-88-generic-lpae (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-5.4.0-88-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-virtual-hwe-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-snapdragon-hwe-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-lowlatency-hwe-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic-lpae-hwe-18.04 (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic-hwe-18.04 (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-azure (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-aws (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-87-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-87-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.4.0-87-generic (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Type Confusion

EUVDB-ID: #VU64881

Risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-33624

CWE-ID: CWE-843 - Type confusion

Exploit availability: Yes

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to a type confusion error within kernel/bpf/verifier.c in the Linux kernel. A an unprivileged BPF program can read arbitrary memory locations via a side-channel attack.

Mitigation

Update the affected package linux to the latest version.

Vulnerable software versions

Ubuntu: 18.04 - 20.04

linux-image-gkeop (Ubuntu package): before 5.4.0.1024.27

linux-image-gcp-lts-20.04 (Ubuntu package): before 5.4.0.1053.63

linux-image-lowlatency (Ubuntu package): before 5.4.0.88.92

linux-image-5.4.0-1053-gcp (Ubuntu package): before 5.4.0-1053.57~18.04.1

linux-image-gke-5.4 (Ubuntu package): before 5.4.0.1053.56~18.04.18

linux-image-kvm (Ubuntu package): before 5.4.0.1047.46

linux-image-gke (Ubuntu package): before 5.4.0.1053.63

linux-image-oracle-lts-20.04 (Ubuntu package): before 5.4.0.1055.55

linux-image-generic-lpae (Ubuntu package): before 5.4.0.88.92

linux-image-5.4.0-1047-kvm (Ubuntu package): before 5.4.0-1047.49

linux-image-5.4.0-1055-oracle (Ubuntu package): before 5.4.0-1055.59~18.04.1

linux-image-aws-lts-20.04 (Ubuntu package): before 5.4.0.1057.60

linux-image-5.4.0-1024-gkeop (Ubuntu package): before 5.4.0-1024.25~18.04.1

linux-image-5.4.0-1059-azure (Ubuntu package): before 5.4.0-1059.62~18.04.1

linux-image-gkeop-5.4 (Ubuntu package): before 5.4.0.1024.25~18.04.25

linux-image-5.4.0-1053-gke (Ubuntu package): before 5.4.0-1053.56~18.04.1

linux-image-5.4.0-88-generic (Ubuntu package): before 5.4.0-88.99

linux-image-azure-lts-20.04 (Ubuntu package): before 5.4.0.1059.57

linux-image-5.4.0-1057-aws (Ubuntu package): before 5.4.0-1057.60~18.04.1

linux-image-oem-osp1 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-oem (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-generic (Ubuntu package): before 5.4.0.88.92

linux-image-5.4.0-88-generic-lpae (Ubuntu package): before 5.4.0-88.99

linux-image-virtual (Ubuntu package): before 5.4.0.88.92

linux-image-5.4.0-88-lowlatency (Ubuntu package): before 5.4.0-88.99

linux-image-virtual-hwe-18.04 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-snapdragon-hwe-18.04 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-oracle (Ubuntu package): before 5.4.0.1055.59~18.04.35

linux-image-lowlatency-hwe-18.04 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-generic-lpae-hwe-18.04 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-generic-hwe-18.04 (Ubuntu package): before 5.4.0.87.98~18.04.78

linux-image-gcp (Ubuntu package): before 5.4.0.1053.39

linux-image-azure (Ubuntu package): before 5.4.0.1059.39

linux-image-aws (Ubuntu package): before 5.4.0.1057.40

linux-image-5.4.0-87-lowlatency (Ubuntu package): before 5.4.0-87.98~18.04.1

linux-image-5.4.0-87-generic-lpae (Ubuntu package): before 5.4.0-87.98~18.04.1

linux-image-5.4.0-87-generic (Ubuntu package): before 5.4.0-87.98~18.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5091-1

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. However, proof of concept for this vulnerability is available.

2) Resource exhaustion

EUVDB-ID: #VU63664

Risk: Low

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3679

CWE-ID: CWE-400 - Resource exhaustion

Exploit availability: No

Description

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

The vulnerability exists due to lack of CPU resource in the Linux kernel tracing module functionality when using trace ring buffer in a specific way. A privileged local user (with CAP_SYS_ADMIN capability) could use this flaw to starve the resources causing denial of service.