From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with UTF8SMTPS id 874BF60A5B for ; Wed, 18 Nov 2020 08:56:57 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with UTF8SMTP id 724CB182DB for ; Wed, 18 Nov 2020 08:56:27 +0100 (CET) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with UTF8SMTPS id 8DA27182CE for ; Wed, 18 Nov 2020 08:56:26 +0100 (CET) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with UTF8SMTP id 554B6438EA; Wed, 18 Nov 2020 08:56:26 +0100 (CET) To: Thomas Lamprecht , Dietmar Maurer , pmg-devel@lists.proxmox.com References: <20201117145743.10561-1-d.csapak@proxmox.com> <925752189.205.1605630434708@webmail.proxmox.com> <536187425.206.1605631117830@webmail.proxmox.com> From: Dominik Csapak Message-ID: <31d52e9d-fe70-acdb-b24c-3554df4c3b13@proxmox.com> Date: Wed, 18 Nov 2020 08:56:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:83.0) Gecko/20100101 Thunderbird/83.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.345 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment NICE_REPLY_A -0.001 Looks like a legit reply (A) RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [wikipedia.org] Subject: Re: [pmg-devel] [PATCH pmg-api/gui] add quarantine self service button X-BeenThere: pmg-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Mail Gateway development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Nov 2020 07:56:57 -0000 On 11/18/20 8:44 AM, Thomas Lamprecht wrote: > On 17.11.20 17:38, Dietmar Maurer wrote: >> >>> On 11/17/2020 5:27 PM Dietmar Maurer wrote: >>> >>> >>> IMHO this is too dangerous. >>> >>> This needs at least some kind of captcha ... >> >> i.e. This would allow direct DOS attacks to the internal mail server. >> > > I found this captcha solution, relatively sophisticated but not a PITA for the > (human) user, Friendly Captcha[0] used by some official European Union websites. > > It uses Proof of Work[2] (i.e. crypto puzzel ones device needs to solve by > computation), the specific library used is "Friendly PoW"[1]. > > If we go for a captcha I'd like something like this (could be rebuild), as > it avoids the issues with picture texts (easily solved by computers, bad > accessibility for humans) and similar captchas. > > > [0]: https://github.com/friendlycaptcha/friendly-challenge > [1]: https://github.com/friendlycaptcha/friendly-pow > [2]: https://de.wikipedia.org/wiki/Proof_of_Work > i'd rather go with a rate limited approach e.g. a file with a mail -> last click time mapping and refuse if the last click time is not older than 5min ? and only 1 per 5 seconds overall? a captcha would be much harder to implement (more dependencies, backend as well as dependent frontend code and in this example it seems the code is only available for js/ts), though if we find a simple solution, i am not against it