From patchwork Sat Sep 25 07:53:13 2021 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: 4734 Return-Path: Received: from mail01.ipfire.org (mail01.haj.ipfire.org [172.28.1.202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) client-signature ECDSA (P-384)) (Client CN "mail01.haj.ipfire.org", Issuer "R3" (verified OK)) by web04.haj.ipfire.org (Postfix) with ESMTPS id 4HGh3N1rvzz3x1J for ; Sat, 25 Sep 2021 07:53:20 +0000 (UTC) Received: from mail02.haj.ipfire.org (mail02.haj.ipfire.org [172.28.1.201]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384 client-signature ECDSA (P-384) client-digest SHA384) (Client CN "mail02.haj.ipfire.org", Issuer "R3" (verified OK)) by mail01.ipfire.org (Postfix) with ESMTPS id 4HGh3L47zRz6nJ; Sat, 25 Sep 2021 07:53:18 +0000 (UTC) Received: from mail02.haj.ipfire.org (localhost [127.0.0.1]) by mail02.haj.ipfire.org (Postfix) with ESMTP id 4HGh3L2NDXz2yDs; Sat, 25 Sep 2021 07:53:18 +0000 (UTC) Received: from mail01.ipfire.org (mail01.haj.ipfire.org [172.28.1.202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) client-signature ECDSA (P-384)) (Client CN "mail01.haj.ipfire.org", Issuer "R3" (verified OK)) by mail02.haj.ipfire.org (Postfix) with ESMTPS id 4HGh3J686Nz2yDs for ; Sat, 25 Sep 2021 07:53:16 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384) server-digest SHA384) (No client certificate requested) by mail01.ipfire.org (Postfix) with ESMTPSA id 4HGh3H57Qbz14b for ; Sat, 25 Sep 2021 07:53:15 +0000 (UTC) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=ipfire.org; s=202003ed25519; t=1632556396; h=from:from: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; bh=MvquuRSscNcXJCF7/3hisLa7yOUD10+I7WnwixwvtYY=; b=be8LfJfoYpJOW9cfvQFbR4KQia1B2iunBuQT7wzVNH2Aioj/LbDVP1ohejiR9mizzAxLM4 /ayyI/DJTRyCdHDA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ipfire.org; s=202003rsa; t=1632556396; h=from:from: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; bh=MvquuRSscNcXJCF7/3hisLa7yOUD10+I7WnwixwvtYY=; b=t4fqV/rbHyfryFFBP6xNrjx+wutfYDTIku4bMgve9X40eC/dpxMW+GDOrXFtecnhvSSPE4 EWgcOJdCFr7n0CQ0zFS2SYSzsMP1ZzLJTF1eb9YqeIol0LZLKKi7cU2XcuNVTAJLBb996Y WoSZO0WHGhMeeMeSD2k+lPFaXdqOIkgk9EsleYJ5UgzNV8xU6k2L4o1Qu51+BsyC1bGDgV 4k/1bQLdS6wg5f2ekuMgntLldyzPKklKsi7ArbwT6xSVguJqwKPNFMVxS7DVUX/vJAG/wz 6bg4qfoTVuZpgZX0D+bcgJuMalVeMEBj8r8xhgWbI0oCZgWbxFt/tu4wTgYz/w== To: "IPFire: Development" From: =?utf-8?q?Peter_M=C3=BCller?= Subject: [RFC PATCH] Unbound: Deny DNS queries of type ANY Message-ID: <2ed9b3f6-28eb-3922-5501-f431df64e5ba@ipfire.org> Date: Sat, 25 Sep 2021 09:53:13 +0200 MIME-Version: 1.0 Content-Language: en-US X-BeenThere: development@lists.ipfire.org X-Mailman-Version: 2.1.29 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" While not inherently malicious, ANY queries are nowadays commonly used in DNS-based DDoS attacks, since nameservers must respond with a _very_ large answer to a very small query. In 2015, Cloudflare stopped responding to them altogether (see: https://blog.cloudflare.com/deprecating-dns-any-meta-query-type/), and several discussions took place in various DNS operator working groups, ultimately resulting in RFC 8482 (https://datatracker.ietf.org/doc/html/rfc8482). Aside from - very uncommon - debugging or enumerating purposes, there is little legitimate reason why a client behind IPFire needs to conduct an ANY query. In fact, no up-to-date implementation of some legitimate software has been observed doing so in the recent past. To prevent IPFire from unintentionally participating in a DDoS attack, this patch changes the handling of ANY queries, forbidding them altogether. Signed-off-by: Peter Müller Acked-by: Bernhard Bitsch --- config/unbound/unbound.conf | 1 + 1 file changed, 1 insertion(+) diff --git a/config/unbound/unbound.conf b/config/unbound/unbound.conf index 9d5e840dd..3848b0f71 100644 --- a/config/unbound/unbound.conf +++ b/config/unbound/unbound.conf @@ -40,6 +40,7 @@ server: harden-large-queries: yes harden-referral-path: yes aggressive-nsec: yes + deny-any: yes # TLS tls-cert-bundle: /etc/ssl/certs/ca-bundle.crt