OpenVPN DDoS risks

Advisory ID	CVE Number	Date discovered	Severity	Advisory revision
STORM-2024-005	CVE-2020-20813	08/20/2023	medium	v6

Vulnerability details

A vulnerability has been identified in the OpenVPN service embedded in SNS products. An attacker could exploit it with specific crafted packets, in order to cause a denial of service of the OpenVPN daemon.

Impacted products

Products	Severity	Detail
Stormshield Network Security	medium	SNS is impacted

Revisions

Version	Date	Description
v1	02/13/2024	Initial release
v2	04/10/2024	Update and disclosed
v3	05/28/2024	Update corrective versions
v4	05/29/2024	Update corrective versions
v5	05/30/2024	Update impacted versions
v6	08/07/2024	Update corrective versions

Stormshield Network Security

CVSS v3.1 Overall Score: 5.1

Analysis

Impacted version

Control Channel in OpenVPN allows remote attackers to cause a denial of service via specifically crafted reset packet.

SNS 4.4.0 to 4.7.2
SNS 4.3.0 to 4.3.25

Workaround solution

Solution

There is no workaround solution.

The following versions fix this vulnerability:

4.7.4
4.3.27

Attack Vector	Attack Complexity	Privileges Required	User Interaction	Scope	Confidentiality Impact	Integrity Impact	Availability impact
Network	Low	None	None	Unchanged	None	None	High

CVSS Base score: 7.5	CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Exploit Code Maturity	Remediation Level	Report Confidence
Proof of concept code	Official fix	Confirmed

CVSS Temporal score: 6.7	CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C)

Confidentiality Requirement	Integrity Requirement	Availability Requirement
Low	Low	Low

CVSS Environmental score: 5.1	CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C/CR:L/IR:L/AR:L/MAV:X/MAC:X/MPR:X/MUI:X/MS:X/MC:X/MI:X/MA:X)