Ubuntu update for linux

Published: 2021-05-11

Risk	Low
Patch available	YES
Number of vulnerabilities	3
CVE-ID	CVE-2021-3489 CVE-2021-3490 CVE-2021-3491
CWE-ID	CWE-125 CWE-787
Exploitation vector	Local
Public exploit	Vulnerability #2 is being exploited in the wild.
Vulnerable software	Ubuntu Operating systems & Components / Operating system linux-image-raspi (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-raspi-nolpae (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 (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-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-generic-64k (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 (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-5.11.0-17-lowlatency (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-17-generic-lpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-17-generic-64k (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-17-generic (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1008-raspi-nolpae (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1008-raspi (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1007-kvm (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1007-gcp (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1007-aws (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1006-oracle (Ubuntu package) Operating systems & Components / Operating system package or component linux-image-5.11.0-1005-azure (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Out-of-bounds read

EUVDB-ID: #VU90367

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-2021-3489

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

Exploit availability: No

Description

The vulnerability allows a local user to execute arbitrary code.

The vulnerability exists due to an out-of-bounds read error within the __bpf_ringbuf_reserve() function in kernel/bpf/ringbuf.c. A local user can execute arbitrary code.

Mitigation

Update the affected package linux to the latest version.

Vulnerable software versions

Ubuntu: 21.04

linux-image-raspi (Ubuntu package): before 5.11.0.1008.6

linux-image-virtual (Ubuntu package): before 5.11.0.17.18

linux-image-raspi-nolpae (Ubuntu package): before 5.11.0.1008.6

linux-image-oracle (Ubuntu package): before 5.11.0.1006.6

linux-image-lowlatency (Ubuntu package): before 5.11.0.17.18

linux-image-kvm (Ubuntu package): before 5.11.0.1007.7

linux-image-gke (Ubuntu package): before 5.11.0.1007.7

linux-image-generic-lpae (Ubuntu package): before 5.11.0.17.18

linux-image-generic-64k (Ubuntu package): before 5.11.0.17.18

linux-image-generic (Ubuntu package): before 5.11.0.17.18

linux-image-gcp (Ubuntu package): before 5.11.0.1007.7

linux-image-azure (Ubuntu package): before 5.11.0.1005.5

linux-image-aws (Ubuntu package): before 5.11.0.1007.7

linux-image-5.11.0-17-lowlatency (Ubuntu package): before 5.11.0-17.18

linux-image-5.11.0-17-generic-lpae (Ubuntu package): before 5.11.0-17.18

linux-image-5.11.0-17-generic-64k (Ubuntu package): before 5.11.0-17.18

linux-image-5.11.0-17-generic (Ubuntu package): before 5.11.0-17.18

linux-image-5.11.0-1008-raspi-nolpae (Ubuntu package): before 5.11.0-1008.8

linux-image-5.11.0-1008-raspi (Ubuntu package): before 5.11.0-1008.8

linux-image-5.11.0-1007-kvm (Ubuntu package): before 5.11.0-1007.7

linux-image-5.11.0-1007-gcp (Ubuntu package): before 5.11.0-1007.7

linux-image-5.11.0-1007-aws (Ubuntu package): before 5.11.0-1007.7

linux-image-5.11.0-1006-oracle (Ubuntu package): before 5.11.0-1006.6

linux-image-5.11.0-1005-azure (Ubuntu package): before 5.11.0-1005.5

CPE2.3

External links

https://ubuntu.com/security/notices/USN-4950-1

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) Out-of-bounds write

EUVDB-ID: #VU55975

Risk: Low

CVSSv4.0: 8.5 [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:A/U:Clear]

CVE-ID: CVE-2021-3490

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

Exploit availability: Yes

Description

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

The vulnerability exists due to a boundary error when processing untrusted input in bpf. The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the Linux kernel did not properly update 32-bit bounds, which could be turned into out of bounds reads and writes in the Linux kernel and therefore, arbitrary code execution. A local user can run a specially crafted program to trigger an out-of-bounds write and execute arbitrary code with elevated privileges.