Ubuntu update for linux

Published: 2021-09-29

Risk	Medium
Patch available	YES
Number of vulnerabilities	6
CVE-ID	CVE-2021-22543 CVE-2021-3679 CVE-2021-3732 CVE-2021-37576 CVE-2021-38204 CVE-2021-38205
CWE-ID	CWE-119 CWE-400 CWE-264 CWE-787 CWE-416 CWE-824
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-oem (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-gke (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-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-aws-hwe (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-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-azure-lts-18.04 (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-4.15.0-159-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-159-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-159-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1124-azure (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1113-snapdragon (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1112-aws (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1109-gcp (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1100-kvm (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1081-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-4.15.0-1028-dell300x (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 6 vulnerabilities.

1) Buffer overflow

EUVDB-ID: #VU56018

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2021-22543

CWE-ID: CWE-119 - Memory corruption

Exploit availability: Yes

Description

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

The vulnerability exists due to a boundary error in Linux kernel when handling VM_IO|VM_PFNMAP vmas in KVM. A local user can can bypass RO checks and cause the pages to get freed while still accessible by the VMM and guest. As a result, an attacker with the ability to start and control a VM to read/write random pages of memory, can trigger memory corruption and execute arbitrary code with elevated privileges.

Mitigation

Update the affected package linux to the latest version.

Vulnerable software versions

Ubuntu: 14.04 - 18.04

linux-image-oem (Ubuntu package): before 5.4.0.202.198

linux-image-oracle (Ubuntu package): before 6.8.0-1017.18~22.04.1

linux-image-gke (Ubuntu package): before 6.8.0-1015.19

linux-image-gcp (Ubuntu package): before 6.8.0-1019.21~22.04.1

linux-image-azure (Ubuntu package): before 6.8.0-1018.21~22.04.1

linux-image-virtual-hwe-16.04 (Ubuntu package): before 4.15.0.210.193

linux-image-lowlatency-hwe-16.04 (Ubuntu package): before 4.15.0.210.193

linux-image-generic-hwe-16.04 (Ubuntu package): before 4.15.0.210.193

linux-image-aws-hwe (Ubuntu package): before Ubuntu Pro (Infra-only)

linux-image-virtual (Ubuntu package): before 4.15.0.159.148

linux-image-snapdragon (Ubuntu package): before 4.15.0.1113.116

linux-image-oracle-lts-18.04 (Ubuntu package): before 4.15.0.1081.91

linux-image-lowlatency (Ubuntu package): before 4.15.0.159.148

linux-image-kvm (Ubuntu package): before 4.15.0.1100.96

linux-image-generic-lpae (Ubuntu package): before 4.15.0.159.148

linux-image-generic (Ubuntu package): before 4.15.0.159.148

linux-image-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1109.128

linux-image-dell300x (Ubuntu package): before 4.15.0.1028.30

linux-image-azure-lts-18.04 (Ubuntu package): before 4.15.0.1124.97

linux-image-aws-lts-18.04 (Ubuntu package): before 4.15.0.1112.115

linux-image-4.15.0-159-lowlatency (Ubuntu package): before 4.15.0-159.167

linux-image-4.15.0-159-generic-lpae (Ubuntu package): before 4.15.0-159.167

linux-image-4.15.0-159-generic (Ubuntu package): before 4.15.0-159.167

linux-image-4.15.0-1124-azure (Ubuntu package): before 4.15.0-1124.137

linux-image-4.15.0-1113-snapdragon (Ubuntu package): before 4.15.0-1113.122

linux-image-4.15.0-1112-aws (Ubuntu package): before 4.15.0-1112.119

linux-image-4.15.0-1109-gcp (Ubuntu package): before 4.15.0-1109.123

linux-image-4.15.0-1100-kvm (Ubuntu package): before 4.15.0-1100.102

linux-image-4.15.0-1081-oracle (Ubuntu package): before 4.15.0-1081.89

linux-image-4.15.0-1028-dell300x (Ubuntu package): before 4.15.0-1028.33

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5094-1

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.