FreeBSD : openvpn -- illegal client float can break VPN session for other users (8604121c-7fc2-11ea-bcac-7781e90b0c8f)

low Nessus Plugin ID 135714


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The remote FreeBSD host is missing one or more security-related updates.


Lev Stipakov and Gert Doering report :

There is a time frame between allocating peer-id and initializing data channel key (which is performed on receiving push request or on async push-reply) in which the existing peer-id float checks do not work right.

If a 'rogue' data channel packet arrives during that time frame from another address and with same peer-id, this would cause client to float to that new address.

The net effect of this behaviour is that the VPN session for the 'victim client' is broken. Since the 'attacker client' does not have suitable keys, it can not inject or steal VPN traffic from the other session. The time window is small and it can not be used to attack a specific client's session, unless some other way is found to make it disconnect and reconnect first.


Update the affected packages.

See Also

Plugin Details

Severity: Low

ID: 135714

File Name: freebsd_pkg_8604121c7fc211eabcac7781e90b0c8f.nasl

Version: 1.3

Type: local

Published: 4/17/2020

Updated: 5/18/2020

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2020-11810


Risk Factor: Low

Score: 2.2


Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.2

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

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: Low

Base Score: 3.7

Temporal Score: 3.2

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

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

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:openvpn, p-cpe:/a:freebsd:freebsd:openvpn-devel, p-cpe:/a:freebsd:freebsd:openvpn-mbedtls, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 4/16/2020

Vulnerability Publication Date: 4/13/2020

Reference Information

CVE: CVE-2020-11810