Ubuntu update for linux-gcp

1) Security restrictions bypass

EUVDB-ID: #VU56929

Risk: Low

CVSSv4.0: 5.9 [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:U/U:Clear]

CVE-ID: CVE-2021-3656

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a malicious guest to escalate privileges on the system.

The vulnerability exists due to improperly imposed security restrictions within the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest.

The vulnerability allows the L2 guest to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.

Mitigation

Update the affected package linux-gcp to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

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-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1108.127

linux-image-4.15.0-1108-gcp (Ubuntu package): before 4.15.0-1108.122

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:linux-image-gke_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp-lts-18.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-4.15.0-1108-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5073-2

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) Security restrictions bypass

EUVDB-ID: #VU56904

Risk: Low

CVSSv4.0: 5.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3653

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a malicious guest to escalate privileges on the system.

The vulnerability exists due to improperly imposed security restrictions within the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "int_ctl" field, this issue could allow a malicious L1 to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest.

As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.

Mitigation

Update the affected package linux-gcp to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

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-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1108.127

linux-image-4.15.0-1108-gcp (Ubuntu package): before 4.15.0-1108.122

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:linux-image-gke_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp-lts-18.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-4.15.0-1108-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5073-2

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Use of uninitialized resource

EUVDB-ID: #VU55263

Risk: Low

CVSSv4.0: 1.1 [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:U/U:Clear]

CVE-ID: CVE-2021-34693

CWE-ID: CWE-908 - Use of Uninitialized Resource

Exploit availability: No

Description

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

The vulnerability exists due to net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.

Mitigation

Update the affected package linux-gcp to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

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-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1108.127

linux-image-4.15.0-1108-gcp (Ubuntu package): before 4.15.0-1108.122

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:linux-image-gke_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp-lts-18.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-4.15.0-1108-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5073-2

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.

4) Out-of-bounds write

EUVDB-ID: #VU55231

Risk: Low

CVSSv4.0: 4.4 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-3612

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error in joystick devices subsystem in Linux kernel. A local user can make a specially crafted JSIOCSBTNMAP IOCTL call, trigger out-of-bounds write and execute arbitrary code with escalated privileges.

Mitigation

Update the affected package linux-gcp to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

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-gcp-lts-18.04 (Ubuntu package): before 4.15.0.1108.127

linux-image-4.15.0-1108-gcp (Ubuntu package): before 4.15.0-1108.122

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:linux-image-gke_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-gcp-lts-18.04_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:linux-image-4.15.0-1108-gcp_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5073-2

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.