Detections
Analytics
Xen oxenstored Bad Permissions (XSA-353)
high Nessus Plugin ID 149088
Language:
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 bad permissions issue. In the Ocaml xenstored implementation, the internal representation of the tree has special cases for the root node, because this node has no parent. Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable.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 according to the vendor advisory.See Also
Plugin Details
Severity: High
ID: 149088
File Name: xen_server_XSA-353.nasl
Version: 1.2
Type: local
Family: Misc.
Published: 4/29/2021
Updated: 4/30/2021
Configuration: Enable paranoid mode
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 6.5
CVSS v2
Risk Factor: High
Base Score: 7.2
Temporal Score: 5.3
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2020-29479
CVSS v3
Risk Factor: High
Base Score: 8.8
Temporal Score: 7.7
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/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: installed_sw/Xen Hypervisor, Settings/ParanoidReport
Exploit Ease: No known exploits are available
Patch Publication Date: 12/15/2020
Vulnerability Publication Date: 12/15/2020
Reference Information
CVE: CVE-2020-29479