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DDoS attacks on our website.

Moved Security
  • We often receive DDoS attacks on our website. Could you please provide a tutorial on how to deploy it on Vercel?

  • @周林锋 DDoS attacks are typically mitigated at the ISP or Firewall level, and should not be actioned at the server level ideally - however, most of this depends on the type of DDoS attack.

    For example, Layer 2 and 3 type attacks (Data and Network from the OSI Model) should always be handled by any traversing path other than the server itself - see below

    42853c8c-8a0b-4ce2-b2b3-97c9b96bed4d-image.png

    In this case, the ISP itself, or the firewall sitting in front of the server should have mitigation processes in place to prevent this type of attack hitting your server directly. Layer 7 attacks are different in their approach, and typically target the application directly. To avoid this, you should deploy a Web Application Firewall (WAF) that can filter out these types of attacks.

    Essentially, the “easy” choice here is Cloudflare, although I note that your server is potentially located in China, so this may not be an option - although AWS (operated by Sinnet) is available - more information here

    https://www.amazonaws.cn/en/new/2021/amazon-waf-available-china/

    If you can provide more information around the infrastructure you have (not here, but via PM for security reasons), I can guide you further.

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    @Hari Ok, no issues. Keep me posted…

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    @mathourthy Good question. They have zero effect from what I can see. It’s not going to stop them from targeting anyone else.

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    @DownPW 🙂 most of this really depends on your desired security model. In all cases with firewalls, less is always more, although it’s never as clear cut as that, and there are always bespoke ports you’ll need to open periodically.

    Heztner’s DDoS protection is superior, and I know they have invested a lot of time, effort, and money into making it extremely effective. However, if you consider that the largest ever DDoS attack hit Cloudflare at 71m rps (and they were able to deflect it), and each attack can last anywhere between 8-24 hours which really depends on how determined the attacker(s) is/are, you can never be fully prepared - nor can you trace it’s true origin.

    DDoS attacks by their nature (Distributed Denial of Service) are conducted by large numbers of devices whom have become part of a “bot army” - and in most cases, the owners of these devices are blissfully unaware that they have been attacked and are under command and control from a nefarious resource. Given that the attacks originate from multiple sources, this allows the real attacker to observe from a distance whilst concealing their own identity and origin in the process.

    If you consider the desired effect of DDoS, it is not an attempt to access ports that are typically closed, but to flood (and eventually overwhelm) the target (such as a website) with millions of requests per second in an attempt to force it offline. Victims of DDoS attacks are often financial services for example, with either extortion or financial gain being the primary objective - in other words, pay for the originator to stop the attack.

    It’s even possible to get DDoS as a service these days - with a credit card, a few clicks of a mouse and a target IP, you can have your own proxy campaign running in minutes which typically involves “booters” or “stressers” - see below for more

    https://heimdalsecurity.com/blog/ddos-as-a-service-attacks-what-are-they-and-how-do-they-work

    @DownPW said in Setting for high load and prevent DDoS (sysctl, iptables, crowdsec or other):

    in short if you have any advice to give to secure the best.

    It’s not just about DDos or firewalls. There are a number of vulnerabilities on all systems that if not patched, will expose that same system to exploit. One of my favourite online testers which does a lot more than most basic ones is below

    https://www.immuniweb.com/websec/

    I’d start with the findings reported here and use that to branch outwards.

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    @crazycells this perhaps? 🙂

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    @mike-jones Hi Mike,

    There are multiple answers to this, so I’m going to provide some of the most important ones here

    JS is a client side library, so you shouldn’t rely on it solely for validation. Any values collected by JS will need to be passed back to the PHP backend for processing, and will need to be fully sanitised first to ensure that your database is not exposed to SQL injection. In order to pass back those values into PHP, you’ll need to use something like

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    Of course, the above is a basic example, but is fully functional. Here, the risk level is low in the sense that you are not attempting to manipulate data, but simply request it. However, this in itself would still be vulnerable to SQL injection attack if the request is not sent as OOP (Object Orientated Programming). Here’s an example of how to get the data safely

    <?php function getid($theid) { global $db; $stmt = $db->prepare("SELECT *FROM data where id = ?"); $stmt->execute([$theid]); while ($result= $stmt->fetch(PDO::FETCH_ASSOC)){ $name = $result['name']; $address = $result['address']; $zip = $result['zip']; } return array( 'name' => $name, 'address' => $address, 'zip' => $zip ); } ?>

    Essentially, using the OOP method, we send placeholders rather than actual values. The job of the function is to check the request and automatically sanitise it to ensure we only return what is being asked for, and nothing else. This prevents typical injections such as “AND 1=1” which of course would land up returning everything which isn’t what you want at all for security reasons.

    When calling the function, you’d simply use

    <?php echo getid($myvalue); ?>

    @mike-jones said in Securing javascript -> PHP mysql calls on Website:

    i am pretty sure the user could just use the path to the php file and just type a web address into the search bar

    This is correct, although with no parameters, no data would be returned. You can actually prevent the PHP script from being called directly using something like

    <?php if(!defined('MyConst')) { die('Direct access not permitted'); } ?>

    then on the pages that you need to include it

    <?php define('MyConst', TRUE); ?>

    Obviously, access requests coming directly are not going via your chosen route, therefore, the connection will die because MyConst does not equal TRUE

    @mike-jones said in Securing javascript -> PHP mysql calls on Website:

    Would it be enough to just check if the number are a number 1-100 and if the drop down is one of the 5 specific words and then just not run the rest of the code if it doesn’t fit one of those perameters?

    In my view, no, as this will expose the PHP file to SQL injection attack without any server side checking.

    Hope this is of some use to start with. Happy to elaborate if you’d like.