Oracle Linux 7 / 8 : Unbreakable Enterprise kernel-container (ELSA-2021-9086)

high Nessus Plugin ID 147203
New! Plugin Severity Now Using CVSS v3

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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-2021-9086 advisory.

- An issue was discovered in the Linux kernel 3.2 through 5.10.16, as used by Xen. Grant mapping operations often occur in batch hypercalls, where a number of operations are done in a single hypercall, the success or failure of each one is reported to the backend driver, and the backend driver then loops over the results, performing follow-up actions based on the success or failure of each operation. Unfortunately, when running in PV mode, the Linux backend drivers mishandle this: Some errors are ignored, effectively implying their success from the success of related batch elements. In other cases, errors resulting from one batch element lead to further batch elements not being inspected, and hence successful ones to not be possible to properly unmap upon error recovery. Only systems with Linux backends running in PV mode are vulnerable. Linux backends run in HVM / PVH modes are not vulnerable. This affects arch/*/xen/p2m.c and drivers/xen/gntdev.c. (CVE-2021-26932)

- In kbd_keycode of keyboard.c, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-144161459 (CVE-2020-0431)

- 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)

- 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)

- An issue was discovered in the Linux kernel 3.11 through 5.10.16, as used by Xen. To service requests to the PV backend, the driver maps grant references provided by the frontend. In this process, errors may be encountered. In one case, an error encountered earlier might be discarded by later processing, resulting in the caller assuming successful mapping, and hence subsequent operations trying to access space that wasn't mapped. In another case, internal state would be insufficiently updated, preventing safe recovery from the error. This affects drivers/block/xen-blkback/blkback.c. (CVE-2021-26930)

- An issue was discovered in the Linux kernel 2.6.39 through 5.10.16, as used in Xen. Block, net, and SCSI backends consider certain errors a plain bug, deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions), it isn't correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode, though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.
(CVE-2021-26931)

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 kernel-uek-container and / or kernel-uek-container-debug packages.

See Also

https://linux.oracle.com/errata/ELSA-2021-9086.html

Plugin Details

Severity: High

ID: 147203

File Name: oraclelinux_ELSA-2021-9086.nasl

Version: 1.4

Type: local

Agent: unix

Published: 3/9/2021

Updated: 9/8/2021

Dependencies: linux_alt_patch_detect.nasl, ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2021-3347

VPR

Risk Factor: High

Score: 8.4

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: 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: 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-container, p-cpe:/a:oracle:linux:kernel-uek-container-debug

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: 3/9/2021

Vulnerability Publication Date: 9/17/2020

Reference Information

CVE: CVE-2020-0431, CVE-2020-16120, CVE-2021-3347, CVE-2021-3348, CVE-2021-26930, CVE-2021-26931, CVE-2021-26932