From owner-freebsd-security@freebsd.org Mon Sep 20 19:21:21 2021 Return-Path: Delivered-To: freebsd-security@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id B21276ABF9F for ; Mon, 20 Sep 2021 19:21:21 +0000 (UTC) (envelope-from mat@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4HCvYY4fs8z4p3j; Mon, 20 Sep 2021 19:21:21 +0000 (UTC) (envelope-from mat@freebsd.org) Received: from mail.j.mat.cc (owncloud.cube.mat.cc [IPv6:2a01:678:4:1::228]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.mat.cc", Issuer "R3" (verified OK)) (Authenticated sender: mat/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 6C18D22E89; Mon, 20 Sep 2021 19:21:21 +0000 (UTC) (envelope-from mat@freebsd.org) Received: from aching.in.mat.cc (unknown [IPv6:2a01:678:42:0:ffc2:a9e4:d09f:c077]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: mat@mat.cc) by mail.j.mat.cc (Postfix) with ESMTPSA id AD2C3942D81; Mon, 20 Sep 2021 19:21:18 +0000 (UTC) Date: Mon, 20 Sep 2021 21:21:17 +0200 From: Mathieu Arnold To: Eugene Grosbein Cc: Ed Maste , freebsd-security@freebsd.org Subject: Re: Important note for future FreeBSD base system OpenSSH update Message-ID: <20210920192117.ylaewdyxcjtl6rsb@aching.in.mat.cc> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="c6o5srltse6xawnc" Content-Disposition: inline In-Reply-To: X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Sep 2021 19:21:21 -0000 --c6o5srltse6xawnc Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Sep 12, 2021 at 05:09:45AM +0700, Eugene Grosbein wrote: > 10.09.2021 1:01, Ed Maste wrote: >=20 > > To check whether a server is using the weak ssh-rsa public key > > algorithm, for host authentication, try to connect to it after > > removing the ssh-rsa algorithm from ssh(1)'s allowed list: > >=20 > > ssh -oHostKeyAlgorithms=3D-ssh-rsa user@host > >=20 > > If the host key verification fails and no other supported host key > > types are available, the server software on that host should be > > upgraded. >=20 > I have some telco equipment (E1/SS7) based on custom Linux distro built b= y a vendor: >=20 > $ ssh -oHostKeyAlgorithms=3D-ssh-rsa user@host > Unable to negotiate with X.X.X.X port 22: no matching host key type found= =2E Their offer: ssh-rsa >=20 > I've already asked the vendor for possible upgrade and was told that no u= pgrade will be available. >=20 > Will I be able to use ssh_config and following command to re-enable the f= eature after planned import? >=20 > HostKeyAlgorithms ssh-rsa Same here, I have many telco and even switches and routers that only support ssh-rsa, will it be possible to use a ssh_config knob to enable it back? --=20 Mathieu Arnold --c6o5srltse6xawnc Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAABCgB9FiEEVhwchfRfuV0unqO5KesJApEdfgIFAmFI3yhfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDU2 MUMxQzg1RjQ1RkI5NUQyRTlFQTNCOTI5RUIwOTAyOTExRDdFMDIACgkQKesJApEd fgKARg/9GwxP+aPnLsUo+ZjxRfKIaUmvUs0phVPSlOsfeIc7IADR6c/2pKufPxX1 Y6i8sFQXJAVf3+cqm0cwlBxonVZ63/rSzFT2l9rfB6xp5EIhe50yLhxJeEt7Vl3z ENGqki0IYOR21ziohja2rr9xz2nzlkZm27rUdkysODoqHkW0OESqMOMFl/lkdc/k uVAj1d1rac34yATtRgE0JSFFnlCJ+PeYotw5w5bh3TcvNsTy7Lhv1EP9S6AcE7S3 5Wa6/hooF++8TwJP6DyaV29l1mB1WBcVceELiUez+4/LyBNflTifY4pZv8E3F/TE Ua9l3wZMeFF0LCqWz0ZU7mNjjcP5bHIBbD43JZpUKqM1ndM0lpufO4K3DOqBr4P3 5BFii+H6r4sbH+mkUc1tIdWYFOYzAt2xicnYs+0AyBz40c1ewTsusB8rs73l3z0r E7qgHWKN7ivZAWvotGn1Rnc9sbfSCesYJU9XtOb3MouTfqNvF1eNPF2B8Jh/hsar 6ckyyqDJeW2YdV5IT1TNGLW0dLTboPI4w2mZBJ1P8P+W4ixSuCaCDHBtmSaeAx4M AQZAMOH6JkgRbwFR+HS4G0Sgx93f+7eAQRsloHQ45eTD6lu75pzT+zSJ5cN07lfZ FAkBzMfuTkfQOSKv2HRPH+eQUBpVPJDbb1TeG417uB/dX9ZYqFo= =4aHI -----END PGP SIGNATURE----- --c6o5srltse6xawnc--