Ubuntu update for linux-azure

Published: 2021-10-18

Risk	Medium
Patch available	YES
Number of vulnerabilities	11
CVE-ID	CVE-2021-41073 CVE-2021-33624 CVE-2021-34556 CVE-2021-35477 CVE-2021-3679 CVE-2021-37159 CVE-2021-37576 CVE-2021-38199 CVE-2021-38201 CVE-2021-38204 CVE-2021-38205
CWE-ID	CWE-269 CWE-843 CWE-200 CWE-203 CWE-400 CWE-415 CWE-787 CWE-362 CWE-125 CWE-416 CWE-824
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #2 is available.
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-azure-edge (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-5.11.0-1019-azure (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 11 vulnerabilities.

1) Improper Privilege Management

EUVDB-ID: #VU68300

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-2021-41073

CWE-ID: CWE-269 - Improper Privilege Management

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to improper privilege management within the loop_rw_iter() function in fs/io_uring.c in Linux kernel. A local user can escalate privileges on the system by using IORING_OP_PROVIDE_BUFFERS to trigger a free of a kernel buffer.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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) 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-azure to the latest version.

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.

3) Information disclosure

EUVDB-ID: #VU64203

Risk: Low

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

CVE-ID: CVE-2021-34556

CWE-ID: CWE-200 - Information exposure

Exploit availability: No

Description

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

The vulnerability exists due to excessive data output by the application. A local user can gain unauthorized access to sensitive information on the system.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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) Observable discrepancy

EUVDB-ID: #VU92412

Risk: Low

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

CVE-ID: CVE-2021-35477

CWE-ID: CWE-203 - Observable discrepancy

Exploit availability: No

Description

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

The vulnerability exists due to observable discrepancy error. A local user can gain access to sensitive information.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.

5) 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.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.

6) Double Free

EUVDB-ID: #VU63575

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-2021-37159

CWE-ID: CWE-415 - Double Free

Exploit availability: No

Description

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

The vulnerability exists due to hso_free_net_device() function in drivers/net/usb/hso.c in the Linux kernel calls unregister_netdev without checking for the NETREG_REGISTERED state. A local user can trigger double free and use-after-free errors and execute arbitrary code with elevated privileges.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.

7) Out-of-bounds write

EUVDB-ID: #VU57101

Risk: Medium

CVSSv4.0: 4.8 [CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-37576

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

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error in arch/powerpc/kvm/book3s_rtas.c in the Linux kernel through 5.13.5 on the powerpc platform. An attacker on KVM guest OS can cause host OS memory corruption via rtas_args.nargs and execute arbitrary code on the host OS.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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

8) Race condition

EUVDB-ID: #VU61208

Risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38199

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

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to fs/nfs/nfs4client.c in the Linux kernel has incorrect connection-setup ordering. A remote attacker with access to a remote NFSv4 server can perform a denial of service (DoS) attack by arranging the server to be unreachable during trunking detection.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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

9) Out-of-bounds read

EUVDB-ID: #VU57137

Risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38201

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: No

Description

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

The vulnerability exists due to a boundary error within the net/sunrpc/xdr.c in the Linux kernel. A remote user can perform multiple NFS 4.2 READ_PLUS operations and cause a denial of service attack.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.

10) Use-after-free

EUVDB-ID: #VU63666

Risk: Low

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

CVE-ID: CVE-2021-38204

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a local attacker to perform a denial of service attack.

The vulnerability exists due to a use-after-free error in the drivers/usb/host/max3421-hcd.c in the Linux kernel. An attacker with physical access to the system can remove a MAX-3421 USB device to perform a denial of service attack.

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

Q & A

Can this vulnerability be exploited remotely?

No. The attacker should have physical access to the system in order to successfully exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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

11) Access of uninitialized pointer

EUVDB-ID: #VU92755

Risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-38205

CWE-ID: CWE-824 - Access of Uninitialized Pointer

Exploit availability: No

Description

The vulnerability allows a local user to manipulate data.

drivers/net/ethernet/xilinx/xilinx_emaclite.c in the Linux kernel before 5.13.3 makes it easier for attackers to defeat an ASLR protection mechanism because it prints a kernel pointer (i.e., the real IOMEM pointer).

Mitigation

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

Vulnerable software versions

Ubuntu: 20.04 - 21.04

linux-image-azure-edge (Ubuntu package): before 5.11.0.1019.20~20.04.18

linux-image-azure (Ubuntu package): before 5.11.0.1019.20

linux-image-5.11.0-1019-azure (Ubuntu package): before 5.11.0-1019.20~20.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5092-3

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.