OpenVPN DDoS risks

Advisory ID CVE Number Date discovered Severity Advisory revision
STORM-2024-005 CVE-2020-20813 08/20/2023 medium v2

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

Stormshield Network Security medium SNS is impacted


Version Date Description
v1 02/13/2024 Initial release
v2 04/10/2024 Update and disclosed

Stormshield Network Security

CVSS v3.1 Overall Score: 5.1      


Impacted version

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

  • SNS 4.7.0 to 4.7.2
  • SNS 4.6.0 to 4.6.10
  • SNS 4.3.0 to 4.3.24
  • SNS 3.11.0 to 3.11.27
  • SNS 3.7.0 to 3.7.39

Workaround solution


There is no workaround solution.

The following versions fix this vulnerability:

  • 4.7.3
  • 4.3.25

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)