From patchwork Mon Aug 20 04:41:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Peter_M=C3=BCller?= X-Patchwork-Id: 1895 Return-Path: Received: from mail01.ipfire.org (mail01.ipfire.org [IPv6:2001:470:7183:25::1]) by web02.i.ipfire.org (Postfix) with ESMTP id 791E360726 for ; Sun, 19 Aug 2018 20:41:52 +0200 (CEST) Received: from mail01.i.ipfire.org (localhost [IPv6:::1]) by mail01.ipfire.org (Postfix) with ESMTP id 0195F112692A; Sun, 19 Aug 2018 19:41:51 +0100 (BST) Received: from mx-nbg.link38.eu (mx-nbg.link38.eu [IPv6:2a03:4000:6:432c:1f9e:48:ac3:199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mx-nbg.link38.eu", Issuer "Let's Encrypt Authority X3" (verified OK)) by mail01.ipfire.org (Postfix) with ESMTPS id EEB9D10F83E0 for ; Sun, 19 Aug 2018 19:41:47 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=link38.eu; s=201803; t=1534704110; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:in-reply-to: references; bh=AZsDmlcRerkEZv6mNJw07YpITigvPRzCur5qXFusmHs=; b=EU7MOtPJOHWcEZ/0FNZaKR3twXuqpkfcRtJEiuMLR6/Mmkqkg3o0Gb1Z1Zc/jSyZpJSmMg 0c+5g5WlGofdNbWZCPyd/Mcw9qzySs51OodA4D6rKQOLcMX1Z+7zq2V+rj6S2L3vi+0Gko muvBB18h2o7PPpkb4nYz84BpMjk+5IIF7lBcN6/AjJSWA+fbw6c+D18TqVCGyu0e6lRBCf b+C4DgSxxz5eFkKMDUZErIo/h6C12F+2ajfBL7PI0b3wtOjyCUui6UTOz5aYYHrbpjYyU2 K0Q8K+fZq8X5SbJh3aBQr4jDA+EO5GcQ2+KaH0WmOrR0dW9D4s5vV1WdIrwBcg== To: "ipfire: Development-List" From: =?utf-8?q?Peter_M=C3=BCller?= Openpgp: preference=signencrypt Autocrypt: addr=peter.mueller@link38.eu; prefer-encrypt=mutual; keydata= xsFNBFrlh/UBEADDNM0LnM9+1NhjgfIz7Ww9Hlx6egK75TJoVa/S9gjI+3DeXn7hsj7vZnQz qSXMhSauU7k4g+F+MmOJP2HRIl0lEo/JNrpAqrAseSnbJp4eq8OTyAL6+Z3SVNJNbcRDOHmw jb/GR8ncURcgYDYV+oCs4csrghtBnm4cWaD/RW10zlB4nQsqQ5G3jzY9aIM+NKRHSAZEbXBZ W6pyDcGRMkwSFTHXpjtFDZ6mVEMxi1nv2W8PMU+uGbs3ud4gzPZ0tT5ICR8bp71qpua4r4RQ o6rB/suiPOptOE5/rk8FiW3ho0y1xDu7bRx8UzdLS9cYCVeSvf9n9YZ6RGOH9O7dS23zfTkS 8iqYol1PmVZrNtpsWBCq4HzFtRJPs6gykFNfj2sVQXU3RHHf2ui0OKm3R0olhLVbKSw2qSPM ajP1vBuVLEMSJmucxlJQ72Im/afnOz3LlNt+/FOB0zneoKGvPpPGSP/Fr5FJYED6/l1DZl2W 8Wb76xq3HGfETHW9kwwqbbQefMu6LNQIw9CnTpSk/R9mt7AnIrKCjxfclLDfz6VBJ0grRDDF PBEVBrj7uZM0UCl/dUX0adjDxBfma/UJZcBlDVX61+41vsX6w094sveKaNdqybAIxqGnhRUq kCHm5P/IYOZrtkao/TsRIW508MJBGmxoUl2qqCj7tXtNy2tiUQARAQABzSdQZXRlciBNw7xs bGVyIDxwZXRlci5tdWVsbGVyQGxpbmszOC5ldT7CwX8EEwECACkFAlrlh/UCGyMFCQlmAYAH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRDZSPIPfXufaDlVD/0elAwSohcC4T5jFtPt hZ1+jU9t46pwBhQ8ohKpo4/wAuVBg5B0FYb0gegcSicYWsNkhTtCjUhExMilLKTaJir5l+3V B/rU/WG7NgLYqmYsGlgHPXdLZAbOMU/0atONFYos1UZnRGmPfhLwRw3g5TBaKrfqaFBzRABE W0R+XuRoXy9ho+lNP5g0Sa+SxtOeBpLQxppObk5WLUqDKxrvHhStgM3PrJASKujsJiw19IUg ws0q+WezH8LPQd3Vc8DP56sl1/h8w2Xklsdxj1NEcO7OIrrKSNIRGyqgqvtmDi6dxh1suGUW Par/VhB+P+u0yVy8H1lZ4SFUsZJFPwHNFSN41USmT/uHf9Z7K1+qXm4zpyexrDQ+ojuXxnB1 y97cHYcYaCZ2Bo+deljXng1NF0I3CdIdhPfLv7FHRBoBw1xs0qJjUfTfSAZsYD0H/jl76bRx 4s8rrECqM7pMnE4aLiP4m6gKJKooH8QAQsmGRYAI8gG/BIHPHZUpZ8J2jRnj6GQ1MpEdcnLE Q0N7QMayDoPq177es7tey5vzofq3bDGW/O9yqUWiz3e7uaGSQnYoRGm2oCCTojvGt37yS0H8 v+ms2fokPNt8UDmpZoLFFPXDwVcnL/KBkPY665xchatKpBOtJ3lRnXdlyRJW1gGda9G5mGFn xLcWumkZ12YKmtixuM7BTQRa5Yf1ARAA4UCkVBvQhks9lApBxvfZ8ekWrticMooBkegL+KQT TPWQHTgdwkFzSneaRq0vFFcgKxmXA54OmT58y0tf09hUvTGK4COs5GTZKP/SYSWZM6xOQqaT 37fros/ma4iSS+IJw/eDh7bWKM5gllz0EuoewaTveGDWeucf7V36mRUPG47GsNk/PgCRsO5Y SLlpfT/3xH02aRnUmWjzHCkJ9EV388cIWaYo9kP4q9rbcl3IyHP0t78XpIIWH6+o/I0FgzwL GJBdJ0eAE3PNIRGYu8nqYlJ+TIpcIrEPitma6nZtiWAITRO2XDb/2o05tUlEbmlN6dUOqM7X Jvj/Z9KkYNgvYNbHXqXJ+j5gzcq0DR7DtDSDnd1WDrYivQMGBDnZR2YfFjBEsmeArdmDTZqY aqYhBN3iMCI9cErZgik6Niz6jrqBMK98geB04vrqZUYprh7zXgPu0A/EwTIJuZ+GGeEKwMVL pBc2NGxUb/kt8nr1JHAnSludD78EW6QVdpcgO4DhHxzhdDk/L8yE53b5UdvXwad5N4T1QS/Y kk80nByinD4vaIIHti9nOvLQJAro1p997YnVeY0wQ2x14Qw1rqeCOeKqB8PxmHvSK6b+nXLg Dv7HuFLovIeQd/IimGLXBDW4Bkn60HApJ5KcX+GwHp5XqPRKPmtjfMsETZn1ESjyc3sAEQEA AcLBZQQYAQIADwUCWuWH9QIbDAUJCWYBgAAKCRDZSPIPfXufaBRaEACMS5Q1BY/O5o+Vn8lD uMUczEVk/8j07gi1EV2ffutwZ5eYrKvXkuoMPEBb7SWqPUKqpTbw1pNjUf5002c2xm2r/OSZ oQMRWDztht+EMhjy0qkixMV+TvS6DcFPb8sd+KOoIBD08EBVUxpeNhAFxaRjGEDboJUwtDAd EDUJts5HnXvBqEcnkOfkwDSUWf9epa1mbyO1sO5NnMtxQY6paB2UGQPNE5/J3eo4f5s4wrxR AaM6OCCOtJxs4u0svmOCwd0D8LQ6higBq+EFesc57ZpG3pkNokrROFWRpx6OpQJUnYi5lWm8 +4xF99QfI9mHIz+jrnPcsfAiKdXb8QkeaDkR7bIU269wwKupfN6bHsKFtOnx7AhMLUddzTHA hTe8cov/tnn5xPvSZhpfknOBx+mffNQBsCETuCxPMqtDN5xFuwBxw4ZKZpKYFk/FUl6As1z4 LY2tNXb/JI58fGiLreunuvxsEkb97hmly1e19IPOTJzawB/aKRQNpIkoE11UBhKyc+kwIfVo ZCTlp+3hpBFqxEjRReSQUKKb9hA4yP3j90Fb353JbNKf9+Y3UtFPJb67koDOGtbJsk19bzPE zO0j/ek+eXxTIf5NxURVuzY6yvg57ZzW7T/tApT/LLfMEmuYz/LiijgON0uTOSp8KflwAt8m eNtEia+FigGVqn+PSQ== Subject: [PATCH 1/2] add hardened SSH server configuration Message-ID: <042ecb9c-4183-5ea5-ee26-56ed9bcc7a61@link38.eu> Date: Sun, 19 Aug 2018 20:41:45 +0200 MIME-Version: 1.0 Content-Language: en-US Authentication-Results: mail01.ipfire.org; dkim=pass header.d=link38.eu; dmarc=pass (policy=none) header.from=link38.eu; spf=pass smtp.mailfrom=peter.mueller@link38.eu X-Spamd-Result: default: False [-9.54 / 11.00]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[link38.eu]; BAYES_HAM(-3.00)[100.00%]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+ip6:2a03:4000:6:432c:1f9e:48:ac3:199]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_ONE(0.00)[1]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[link38.eu:+]; RCVD_IN_DNSWL_MED(-2.00)[9.9.1.0.3.c.a.0.8.4.0.0.e.9.f.1.c.2.3.4.6.0.0.0.0.0.0.4.3.0.a.2.list.dnswl.org : 127.0.6.2]; DMARC_POLICY_ALLOW(-0.25)[link38.eu,none]; MX_GOOD(-0.01)[cached: mx-nbg.link38.eu]; RCVD_COUNT_ZERO(0.00)[0]; FROM_EQ_ENVFROM(0.00)[]; IP_SCORE(-3.78)[ip: (-9.90), ipnet: 2a03:4000::/32(-4.95), asn: 197540(-3.96), country: DE(-0.09)]; ASN(0.00)[asn:197540, ipnet:2a03:4000::/32, country:DE]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[] X-Spam-Status: No, score=-9.54 X-Rspamd-Server: mail01.i.ipfire.org X-BeenThere: development@lists.ipfire.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: IPFire development talk List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: development-bounces@lists.ipfire.org Sender: "Development" In order to harden OpenSSH server in IPFire, using the upstream default configuration and edit it via sed commands in LFS file is error-prone and does not scale. Thereof we ship a custom and more secure OpenSSH server configuration which is copied into the image during build time. Fixes #11750 Fixes #11751 Partially fixes #11538 Signed-off-by: Peter Müller --- config/ssh/sshd_config | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 config/ssh/sshd_config diff --git a/config/ssh/sshd_config b/config/ssh/sshd_config new file mode 100644 index 000000000..7acf48109 --- /dev/null +++ b/config/ssh/sshd_config @@ -0,0 +1,68 @@ +# ultra-secure OpenSSH server configuration + +# only allow version 2 of SSH protocol +Protocol 2 + +# listen on these interfaces and protocols +AddressFamily any +ListenAddress 0.0.0.0 +ListenAddress :: + +# limit authentication thresholds +LoginGraceTime 20s +MaxAuthTries 3 +MaxSessions 5 + +# limit maximum instanctes +MaxStartups 5 + +# ensure proper logging +SyslogFacility AUTH +LogLevel INFO + +# always turn on strict mode +StrictModes yes + +# only allow safe crypto algorithms (may break some _very_ outdated clients) +# see also: https://stribika.github.io/2015/01/04/secure-secure-shell.html +KexAlgorithms curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256 +Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes256-ctr +MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com + +# enable data compression after successful login +Compression yes + +# only allow cryptographically safe SSH host keys (adjust paths if needed) +HostKey /etc/ssh/ssh_host_ed25519_key +HostKey /etc/ssh/ssh_host_ecdsa_key +HostKey /etc/ssh/ssh_host_rsa_key + +# only allow login via public key +PubkeyAuthentication yes +PasswordAuthentication no +ChallengeResponseAuthentication no +PermitEmptyPasswords no +AuthenticationMethods publickey + +# ignore user ~/.rhost* files +IgnoreRhosts yes + +# ignore user known hosts file +IgnoreUserKnownHosts yes + +# ignore user environments +PermitUserEnvironment no + +# do not allow any kind of forwarding (provides only low security) +# some of them might need to be re-enabled if SSH server is a jump platform +X11Forwarding no +AllowTcpForwarding no +AllowAgentForwarding no +PermitTunnel no +GatewayPorts no +PermitOpen none + +# close broken session (clients went offline, ...) automagically +TCPKeepAlive yes + +# EOF