CVE-2020-11810 Information

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.

CVSS Vector

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

Reference

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/package-announce@lists.fedoraproject.org/message/FGHHV4YZANZW45KZTJJGVGPFMSXYRCKZ/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JII7RYYYRBPQNEGGVSOXCM7JUZ43T3VH/ https://patchwork.openvpn.net/patch/1079/ https://security-tracker.debian.org/tracker/CVE-2020-11810

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

LOW

Base Severity

3.7