Ubuntu 20.04 LTS : Linux kernel vulnerabilities (USN-5265-1)

high Nessus Plugin ID 157351

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-5265-1 advisory.

- A vulnerability was found in Linux kernel, where a use-after-frees in nouveau's postclose() handler could happen if removing device (that is not common to remove video card physically without power-off, but same happens if unbind the driver). (CVE-2020-27820)

- A flaw use-after-free in function sco_sock_sendmsg() of the Linux kernel HCI subsystem was found in the way user calls ioct UFFDIO_REGISTER or other way triggers race condition of the call sco_conn_del() together with the call sco_sock_sendmsg() with the expected controllable faulting memory page. A privileged local user could use this flaw to crash the system or escalate their privileges on the system.
(CVE-2021-3640)

- A use-after-free flaw was found in the Linux kernel's Bluetooth subsystem in the way user calls connect to the socket and disconnect simultaneously due to a race condition. This flaw allows a user to crash the system or escalate their privileges. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. (CVE-2021-3752)

- A flaw was found in the Linux SCTP stack. A blind attacker may be able to kill an existing SCTP association through invalid chunks if the attacker knows the IP-addresses and port numbers being used and the attacker can send packets with spoofed IP addresses. (CVE-2021-3772)

- A race condition was found in the Linux kernel's ebpf verifier between bpf_map_update_elem and bpf_map_freeze due to a missing lock in kernel/bpf/syscall.c. In this flaw, a local user with a special privilege (cap_sys_admin or cap_bpf) can modify the frozen mapped address space. This flaw affects kernel versions prior to 5.16 rc2. (CVE-2021-4001)

- An out-of-bounds (OOB) memory write flaw was found in the NFSD in the Linux kernel. Missing sanity may lead to a write beyond bmval[bmlen-1] in nfsd4_decode_bitmap4 in fs/nfsd/nfs4xdr.c. In this flaw, a local attacker with user privilege may gain access to out-of-bounds memory, leading to a system integrity and confidentiality threat. (CVE-2021-4090)

- A flaw was found in the KVM's AMD code for supporting the Secure Encrypted Virtualization-Encrypted State (SEV-ES). A KVM guest using SEV-ES can trigger out-of-bounds reads and writes in the host kernel via a malicious VMGEXIT for a string I/O instruction (for example, outs or ins) using the exit reason SVM_EXIT_IOIO. This issue results in a crash of the entire system or a potential guest-to-host escape scenario. (CVE-2021-4093)

- A use-after-free flaw was found in nci_request in net/nfc/nci/core.c in NFC Controller Interface (NCI) in the Linux kernel. This flaw could allow a local attacker with user privileges to cause a data race problem while the device is getting removed, leading to a privilege escalation problem. (CVE-2021-4202)

- dp_link_settings_write in drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c in the Linux kernel through 5.14.14 allows a heap-based buffer overflow by an attacker who can write a string to the AMD GPU display drivers debug filesystem. There are no checks on size within parse_write_buffer_into_params when it uses the size of copy_from_user to copy a userspace buffer into a 40-byte heap buffer. (CVE-2021-42327)

- A heap-based buffer overflow flaw was found in the Linux kernel FireDTV media card driver, where the user calls the CA_SEND_MSG ioctl. This flaw allows a local user of the host machine to crash the system or escalate privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. (CVE-2021-42739)

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-5265-1

Plugin Details

Severity: High

ID: 157351

File Name: ubuntu_USN-5265-1.nasl

Version: 1.9

Type: local

Agent: unix

Published: 2/3/2022

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: 7.9

Temporal Score: 6.2

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

CVSS Score Source: CVE-2021-3752

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.9

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:P/RL:O/RC:C

CVSS Score Source: CVE-2021-4093

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1028-azure, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.11.0-1029-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-1012-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-1029-oem, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-28-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-28-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-28-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.13.0-28-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: 2/3/2022

Vulnerability Publication Date: 10/20/2021

Reference Information

CVE: CVE-2020-27820, CVE-2021-3640, CVE-2021-3752, CVE-2021-3772, CVE-2021-4001, CVE-2021-4090, CVE-2021-4093, CVE-2021-4202, CVE-2021-42327, CVE-2021-42739

USN: 5265-1