Ubuntu 16.04 LTS : Linux kernel vulnerabilities (USN-4876-1)

high Nessus Plugin ID 148001

Synopsis

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

Description

The remote Ubuntu 16.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4876-1 advisory.

- An issue was discovered in the Linux kernel through 5.10.1, as used with Xen through 4.14.x. The Linux kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped.
However, the handler may not have time to run if the frontend quickly toggles between the states connect and disconnect. As a consequence, the block backend may re-use a pointer after it was freed. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.
(CVE-2020-29569)

- mwifiex_cmd_802_11_ad_hoc_start in drivers/net/wireless/marvell/mwifiex/join.c in the Linux kernel through 5.10.4 might allow remote attackers to execute arbitrary code via a long SSID value, aka CID-5c455c5ab332.
(CVE-2020-36158)

- fs/nfsd/nfs3xdr.c in the Linux kernel through 5.10.8, when there is an NFS export of a subdirectory of a filesystem, allows remote attackers to traverse to other parts of the filesystem via READDIRPLUS. NOTE:
some parties argue that such a subdirectory export is not intended to prevent this attack; see also the exports(5) no_subtree_check default behavior (CVE-2021-3178)

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-4876-1

Plugin Details

Severity: High

ID: 148001

File Name: ubuntu_USN-4876-1.nasl

Version: 1.6

Type: local

Agent: unix

Published: 3/23/2021

Updated: 1/9/2024

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

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2020-36158

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

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

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

CVSS Score Source: CVE-2020-29569

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1089-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1123-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1147-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1151-snapdragon, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-powerpc-e500mc, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-powerpc-smp, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-powerpc64-emb, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-204-powerpc64-smp

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

Exploit Ease: No known exploits are available

Patch Publication Date: 3/16/2021

Vulnerability Publication Date: 12/15/2020

Reference Information

CVE: CVE-2020-29569, CVE-2020-36158, CVE-2021-3178

USN: 4876-1