Detections
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Xen xenstored watch DoS (XSA-324)

medium Nessus Plugin ID 144713

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Synopsis

The remote Xen hypervisor installation is missing a security update.

Description

According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a denial of service vulnerability due to an issue with max payload length in xenstored. A malicious guest can exploit this, by registering a 'watch' with using a very large tag, to cause an error condition in xenstored. This error can result in a NULL pointer dereference, which can crash xenstored.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Apply the appropriate patch or workaround according to the vendor advisory.

See Also

https://xenbits.xen.org/xsa/advisory-324.html

Plugin Details

Severity: Medium

ID: 144713

File Name: xen_server_XSA-324.nasl

Version: 1.3

Type: local

Family: Misc.

Published: 1/5/2021

Updated: 6/3/2021

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.6

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

CVSS Score Source: CVE-2020-29484

CVSS v3

Risk Factor: Medium

Base Score: 6

Temporal Score: 5.2

Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/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: 12/15/2020

Vulnerability Publication Date: 12/15/2020

Reference Information

CVE: CVE-2020-29484

IAVB: 2020-B-0077-S