Detections
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Xen evtchn_reset() race conditions privelege escalation (XSA-339)

high Nessus Plugin ID 141502

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

A privilege escalation vulnerability exists in EVTCHNOP_reset (potentially by a guest on itself) or XEN_DOMCTL_soft_reset due to a race condition present in evtchn_reset(). An authenticated, local attacker can exploit this, via a violation of various internal assumptions, to gain elevate their privilege to that of the host.

Solution

Apply the appropriate patch according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-343.html

Plugin Details

Severity: High

ID: 141502

File Name: xen_server_XSA-343.nasl

Version: 1.4

Type: local

Family: Misc.

Published: 10/19/2020

Updated: 11/13/2020

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 4.4

Temporal Score: 3.3

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

CVSS Score Source: CVE-2020-25599

CVSS v3

Risk Factor: High

Base Score: 7

Temporal Score: 6.1

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:xen:xen

Required KB Items: Settings/ParanoidReport, installed_sw/Xen Hypervisor

Exploit Ease: No known exploits are available

Patch Publication Date: 9/22/2020

Vulnerability Publication Date: 9/22/2020

Reference Information

CVE: CVE-2020-25599

IAVB: 2020-B-0056-S