Ubuntu 18.04 LTS / 20.04 LTS / 20.10 / 21.04 : OpenVPN vulnerabilities (USN-4933-1)

high Nessus Plugin ID 149252
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Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS / 20.10 / 21.04 host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-4933-1 advisory.

- An issue was discovered in OpenVPN 2.4.x before 2.4.9. An attacker can inject a data channel v2 (P_DATA_V2) packet using a victim's peer-id. Normally such packets are dropped, but if this packet arrives before the data channel crypto parameters have been initialized, the victim's connection will be dropped.
This requires careful timing due to the small time window (usually within a few seconds) between the victim client connection starting and the server PUSH_REPLY response back to the client. This attack will only work if Negotiable Cipher Parameters (NCP) is in use. (CVE-2020-11810)

- OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks. (CVE-2020-15078)

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

Solution

Update the affected openvpn package.

See Also

https://ubuntu.com/security/notices/USN-4933-1

Plugin Details

Severity: High

ID: 149252

File Name: ubuntu_USN-4933-1.nasl

Version: 1.4

Type: local

Agent: unix

Published: 5/4/2021

Updated: 5/20/2021

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2020-15078

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

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

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.10, cpe:/o:canonical:ubuntu_linux:21.04, p-cpe:/a:canonical:ubuntu_linux:openvpn

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 5/4/2021

Vulnerability Publication Date: 4/24/2020

Reference Information

CVE: CVE-2020-11810, CVE-2020-15078

USN: 4933-1