CVE-2020-11810

low
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Description

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.

References

https://bugzilla.suse.com/show_bug.cgi?id=1169925

https://community.openvpn.net/openvpn/ticket/1272

https://github.com/OpenVPN/openvpn/commit/37bc691e7d26ea4eb61a8a434ebd7a9ae76225ab

https://lists.fedoraproject.org/archives/list/[email protected]/message/FGHHV4YZANZW45KZTJJGVGPFMSXYRCKZ/

https://lists.fedoraproject.org/archives/list/[email protected]/message/JII7RYYYRBPQNEGGVSOXCM7JUZ43T3VH/

https://patchwork.openvpn.net/patch/1079/

https://security-tracker.debian.org/tracker/CVE-2020-11810

Details

Source: MITRE

Published: 2020-04-27

Updated: 2020-05-14

Type: CWE-362

Risk Information

CVSS v2

Base Score: 4.3

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

Impact Score: 2.9

Exploitability Score: 8.6

Severity: MEDIUM

CVSS v3

Base Score: 3.7

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Impact Score: 1.4

Exploitability Score: 2.2

Severity: LOW

Tenable Plugins

View all (8 total)

IDNameProductFamilySeverity
149641openSUSE Security Update : openvpn (openSUSE-2021-734)NessusSuSE Local Security Checks
critical
149458SUSE SLED15 / SLES15 Security Update : openvpn (SUSE-SU-2021:1577-1)NessusSuSE Local Security Checks
critical
149252Ubuntu 18.04 LTS / 20.04 LTS / 20.10 / 21.04 : OpenVPN vulnerabilities (USN-4933-1)NessusUbuntu Local Security Checks
high
139090Amazon Linux AMI : openvpn (ALAS-2020-1410)NessusAmazon Linux Local Security Checks
low
136297Fedora 30 : openvpn (2020-969414e05b)NessusFedora Local Security Checks
low
136000Fedora 31 : openvpn (2020-e56f2deb30)NessusFedora Local Security Checks
low
135717Slackware 14.0 / 14.1 / 14.2 / current : openvpn (SSA:2020-107-01)NessusSlackware Local Security Checks
low
135714FreeBSD : openvpn -- illegal client float can break VPN session for other users (8604121c-7fc2-11ea-bcac-7781e90b0c8f)NessusFreeBSD Local Security Checks
low