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Ubuntu 18.04 LTS / 20.04 LTS : Linux kernel vulnerabilities (USN-4917-1)

high Nessus Plugin ID 148690

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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4917-1 advisory.

 - BPF JIT compilers in the Linux kernel through 5.11.12 have incorrect computation of branch displacements, allowing them to execute arbitrary code within the kernel context. This affects arch/x86/net/bpf_jit_comp.c and arch/x86/net/bpf_jit_comp32.c. (CVE-2021-29154)

 - Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562. (CVE-2021-3492)

 - The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges. (CVE-2021-3493)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected kernel package.

See Also

https://ubuntu.com/security/notices/USN-4917-1

Plugin Details

Severity: High

ID: 148690

File Name: ubuntu_USN-4917-1.nasl

Version: 1.11

Type: local

Agent: unix

Published: 4/16/2021

Updated: 1/9/2024

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 9.7

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.3

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

CVSS Score Source: CVE-2021-3493

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.5

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.10.0-1022-oem, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1039-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1042-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-73-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-73-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1014-gkeop, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1034-raspi, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1038-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1042-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1043-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1045-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1046-azure, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-72-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-72-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-72-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-50-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-50-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-50-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-50-lowlatency

Required KB Items: Host/cpu, Host/Debian/dpkg-l, Host/Ubuntu, Host/Ubuntu/release

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/15/2021

Vulnerability Publication Date: 4/8/2021

CISA Known Exploited Vulnerability Due Dates: 11/10/2022

Exploitable With

CANVAS (CANVAS)

Core Impact

Metasploit (2021 Ubuntu Overlayfs LPE)

Reference Information

CVE: CVE-2021-29154, CVE-2021-3492, CVE-2021-3493

USN: 4917-1