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Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-4910-1)

high Nessus Plugin ID 148492

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Synopsis

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

Description

The remote Ubuntu 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4910-1 advisory.

 - A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality. (CVE-2021-20239)

 - An out-of-bounds access flaw was found in the Linux kernel's implementation of the eBPF code verifier in the way a user running the eBPF script calls dev_map_init_map or sock_map_alloc. This flaw allows a local user to crash the system or possibly escalate their privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. (CVE-2021-20268)

 - 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)

 - An issue was discovered in the Linux kernel through 5.10.11. PI futexes have a kernel stack use-after-free during fault handling, allowing local users to execute code in the kernel, aka CID-34b1a1ce1458.
 (CVE-2021-3347)

 - nbd_add_socket in drivers/block/nbd.c in the Linux kernel through 5.10.12 has an ndb_queue_rq use-after- free that could be triggered by local attackers (with access to the nbd device) via an I/O request at a certain point during device setup, aka CID-b98e762e3d71. (CVE-2021-3348)

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-4910-1

Plugin Details

Severity: High

ID: 148492

File Name: ubuntu_USN-4910-1.nasl

Version: 1.5

Type: local

Agent: unix

Published: 4/14/2021

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: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.6

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

CVSS Score Source: CVE-2021-3347

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

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:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-49-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-49-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-49-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.8.0-49-lowlatency

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/13/2021

Vulnerability Publication Date: 1/19/2021

Reference Information

CVE: CVE-2021-20239, CVE-2021-20268, CVE-2021-3178, CVE-2021-3347, CVE-2021-3348

USN: 4910-1