Oracle Linux 7 / 8 : Unbreakable Enterprise kernel (ELSA-2021-9450)

medium Nessus Plugin ID 153442
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Synopsis

The remote Oracle Linux host is missing one or more security updates.

Description

The remote Oracle Linux 7 / 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2021-9450 advisory.

- kernel: SVM nested virtualization issue in KVM (AVIC support) (CVE-2021-3653)

- An issue was discovered in the Linux kernel before 5.9. arch/x86/kvm/svm/sev.c allows attackers to cause a denial of service (soft lockup) by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions), aka CID-7be74942f184. (CVE-2020-36311)

- A use-after-free in function hci_sock_bound_ioctl() of the Linux kernel HCI subsystem was found in the way user calls ioct HCIUNBLOCKADDR or other way triggers race condition of the call hci_unregister_dev() together with one of the calls hci_sock_blacklist_add(), hci_sock_blacklist_del(), hci_get_conn_info(), hci_get_auth_info(). A privileged local user could use this flaw to crash the system or escalate their privileges on the system. This flaw affects the Linux kernel versions prior to 5.13-rc5. (CVE-2021-3573)

- kernel: race condition in net/can/bcm.c leads to local privilege escalation (CVE-2021-3609)

- An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users with the ability to start and control a VM to read/write random pages of memory and can result in local privilege escalation. (CVE-2021-22543)

- A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the int_ctl field, this issue could allow a malicious L1 to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape. (CVE-2021-3653) (CVE-2021-3656)

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://linux.oracle.com/errata/ELSA-2021-9450.html

Plugin Details

Severity: Medium

ID: 153442

File Name: oraclelinux_ELSA-2021-9450.nasl

Version: 1.2

Type: local

Agent: unix

Published: 9/16/2021

Updated: 9/16/2021

Dependencies: linux_alt_patch_detect.nasl, ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2021-3573

VPR

Risk Factor: High

Score: 8.4

CVSS v2

Risk Factor: Medium

Base Score: 6.9

Temporal Score: 5.1

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

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

CVSS v3

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.6

Vector: CVSS:3.0/AV:L/AC:H/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:oracle:linux:7, cpe:/o:oracle:linux:8, p-cpe:/a:oracle:linux:kernel-uek, p-cpe:/a:oracle:linux:kernel-uek-debug, p-cpe:/a:oracle:linux:kernel-uek-debug-devel, p-cpe:/a:oracle:linux:kernel-uek-devel, p-cpe:/a:oracle:linux:kernel-uek-doc, p-cpe:/a:oracle:linux:kernel-uek-tools, p-cpe:/a:oracle:linux:kernel-uek-tools-libs, p-cpe:/a:oracle:linux:perf, p-cpe:/a:oracle:linux:python-perf

Required KB Items: Host/OracleLinux, Host/RedHat/release, Host/RedHat/rpm-list, Host/local_checks_enabled

Exploit Ease: No known exploits are available

Patch Publication Date: 9/16/2021

Vulnerability Publication Date: 4/7/2021

Reference Information

CVE: CVE-2020-36311, CVE-2021-3573, CVE-2021-3609, CVE-2021-3653, CVE-2021-3656, CVE-2021-22543