Linux Kernel Detection of MDS vulnerabilities (MDSUM/RIDL) (MFBDS/RIDL/ZombieLoad) (MLPDS/RIDL) (MSBDS/Fallout)

medium Nessus Plugin ID 126244
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Synopsis

The remote Linux kernel is affected by a series of information disclosure vulnerabilities.

Description

According to the remote Linux kernel, this system is vulnerable to the following information disclosure vulnerabilities:

- MSBDS leaks Store Buffer Entries which can be speculatively forwarded to a dependent load (store-to-load forwarding) as an optimization. The forward can also happen to a faulting or assisting load operation for a different memory address, which can cause an issue under certain conditions. Store buffers are partitioned between Hyper-Threads so cross thread forwarding is not possible. But if a thread enters or exits a sleep state the store buffer is repartitioned which can expose data from one thread to the other.
(MSBDS/Fallout) (CVE-2018-12126)

- MLDPS leaks Load Port Data. Load ports are used to perform load operations from memory or I/O. The received data is then forwarded to the register file or a subsequent operation. In some implementations the Load Port can contain stale data from a previous operation which can be forwarded to faulting or assisting loads under certain conditions, which again can cause an issue eventually. Load ports are shared between Hyper-Threads so cross thread leakage is possible. (MLPDS/RIDL) (CVE-2018-12127)

MFBDS leaks Fill Buffer Entries. Fill buffers are used internally to manage L1 miss situations and to hold data which is returned or sent in response to a memory or I/O operation. Fill buffers can forward data to a load operation and also write data to the cache. When the fill buffer is deallocated it can retain the stale data of the preceding operations which can then be forwarded to a faulting or assisting load operation, which can cause an issue under certain conditions. Fill buffers are shared between Hyper-Threads so cross thread leakage is possible. (MFBDS/RIDL/ZombieLoad) (CVE-2018-12130)

- MDSUM is a special case of MSBDS, MFBDS and MLPDS. An uncacheable load from memory that takes a fault or assist can leave data in a microarchitectural structure that may later be observed using one of the same methods used by MSBDS, MFBDS or MLPDS. (MDSUM/RIDL) (CVE-2019-11091)

To address these issues, update the kernel packages on your Linux system, disable Simultaneous Multi-Threading (SMT) or otherwise configure it to a non-vulnerable state, and apply microcode fixes to your hardware. Consult your Linux distribution and processor hardware vendors for details and patches.

Solution

1. Ensure the latest kernel and package updates are applied to your linux packages for your OS distribution.
2. Either disable SMT or configure it to a non-vulnerable state.
Consult your processor manufacturer for details.
3. Apply the appropriate microcode fix for your hardware. Consult your processor manufacturer for details.

See Also

https://mdsattacks.com/

https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html

Plugin Details

Severity: Medium

ID: 126244

File Name: mds_kernel_reporting_linux.nasl

Version: 1.2

Type: local

Family: Misc.

Published: 6/25/2019

Updated: 10/18/2019

Dependencies: ssh_get_info2.nasl

Configuration: Enable paranoid mode

Risk Information

CVSS Score Source: CVE-2019-11091

VPR

Risk Factor: High

Score: 8.5

CVSS v2

Risk Factor: Medium

Base Score: 4.7

Temporal Score: 3.5

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

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

CVSS v3

Risk Factor: Medium

Base Score: 5.6

Temporal Score: 4.9

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

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

Vulnerability Information

CPE: cpe:/o:linux:linux_kernel

Required KB Items: Host/Linux, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 5/14/2019

Vulnerability Publication Date: 5/14/2019

Reference Information

CVE: CVE-2018-12126, CVE-2018-12127, CVE-2018-12130, CVE-2019-11091