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

medium Nessus Plugin ID 148001
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Synopsis

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

Description

The remote Ubuntu 16.04 LTS host has packages installed that are 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)

- ** DISPUTED ** 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 this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-4876-1

Plugin Details

Severity: Medium

ID: 148001

File Name: ubuntu_USN-4876-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 3/23/2021

Updated: 3/23/2021

Dependencies: ssh_get_info.nasl, linux_alt_patch_detect.nasl

Risk Information

CVSS Score Source: CVE-2020-36158

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: Medium

Base Score: 6.7

Temporal Score: 5.8

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.4.0-1087-aws, 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-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-lts-utopic, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-lts-vivid, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-lts-wily, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lpae-lts-xenial, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lts-utopic, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lts-vivid, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lts-wily, p-cpe:/a:canonical:ubuntu_linux:linux-image-generic-lts-xenial, p-cpe:/a:canonical:ubuntu_linux:linux-image-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-lts-utopic, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-lts-vivid, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-lts-wily, p-cpe:/a:canonical:ubuntu_linux:linux-image-lowlatency-lts-xenial, p-cpe:/a:canonical:ubuntu_linux:linux-image-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-snapdragon, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-lts-utopic, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-lts-vivid, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-lts-wily, p-cpe:/a:canonical:ubuntu_linux:linux-image-virtual-lts-xenial

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