17 April 2020
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.1359 openvpn -- illegal client float can break VPN session for other users 17 April 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: openvpn Publisher: FreeBSD Operating System: FreeBSD UNIX variants (UNIX, Linux, OSX) Impact/Access: Denial of Service -- Remote with User Interaction Resolution: Patch/Upgrade CVE Names: CVE-2020-11810 Original Bulletin: http://www.vuxml.org/freebsd/8604121c-7fc2-11ea-bcac-7781e90b0c8f.html Comment: This advisory references vulnerabilities in products which run on platforms other than FreeBSD. It is recommended that administrators running openvpn check for an updated version of the software for their operating system. - --------------------------BEGIN INCLUDED TEXT-------------------- openvpn -- illegal client float can break VPN session for other users Affected packages openvpn < 2.4.8_3 openvpn-mbedtls < 2.4.8_3 openvpn-devel < 202016 Details VuXML ID 8604121c-7fc2-11ea-bcac-7781e90b0c8f Discovery 2020-04-13 Entry 2020-04-16 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. [source] References CVE CVE-2020-11810 URL https://community.openvpn.net/openvpn/ticket/1272 URL https://github.com/OpenVPN/openvpn/commit/ f7b318f811bb43c0d3aa7f337ec6242ed2c33881 URL https://patchwork.openvpn.net/patch/1077/ URL https://sourceforge.net/p/openvpn/openvpn/ci/ f7b318f811bb43c0d3aa7f337ec6242ed2c33881/ URL https://email@example.com/ msg19720.html - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. 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