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Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-4577-1)

high Nessus Plugin ID 141449

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Synopsis

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

Description

The remote Ubuntu 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4577-1 advisory.

 - Use-after-free vulnerability in the Linux kernel exploitable by a local attacker due to reuse of a DCCP socket with an attached dccps_hc_tx_ccid object as a listener after being released. Fixed in Ubuntu Linux kernel 5.4.0-51.56, 5.3.0-68.63, 4.15.0-121.123, 4.4.0-193.224, 3.13.0.182.191 and 3.2.0-149.196.
 (CVE-2020-16119)

 - Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef (ovl:
 stack file ops). This was fixed in kernel version 5.8 by commits 56230d9 (ovl: verify permissions in ovl_path_open()), 48bd024 (ovl: switch to mounter creds in readdir) and 05acefb (ovl: check permission to open real file). Additionally, commits 130fdbc (ovl: pass correct flags for opening real directory) and 292f902 (ovl: call secutiry hook in ovl_real_ioctl()) in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da (ovl: do not fail because of O_NOATIMEi) in kernel 5.11. (CVE-2020-16120)

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-4577-1

Plugin Details

Severity: High

ID: 141449

File Name: ubuntu_USN-4577-1.nasl

Version: 1.6

Type: local

Agent: unix

Published: 10/14/2020

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: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2020-16119

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

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:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.0.0-1049-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.0.0-1069-oem-osp1, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1035-raspi2, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-1038-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-68-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.3.0-68-lowlatency

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/14/2020

Vulnerability Publication Date: 10/14/2020

Reference Information

CVE: CVE-2020-16119, CVE-2020-16120

USN: 4577-1