Suppose, I have a static IP on my PC and is known to others. None of my softwares listen for remote connection. Is it still possible for someone to DOS attack me in such cases? If yes, how it is possible?


DDoS is not specific to HTTP or any service, a Distributed Denial of Service simply means that are multiples sources for the attacker trying to make it so your network connection is non functional.

A denial of service could happen by making your system crash or become unresponsive (if its not on, it won't respond), by filling up all your bandwidth (your pipe), or most simply by physically severing the connection. Distributed denial of services attacks can be started by using multiple clients the attacker controls or by tricking innocent clients to participate.

Refer to the OSI Model or the TCP Layers. HTTP is going to be at the application layer, but you can attack at any layer to cause denial of service.

A very simple example of a lower level DDoS attack, would be the smurf attack. In this attack you take advantage of a broadcast message to all stations on network responding to the spoofed source target, which is the victim.

A similar attack, is the DNS amplification attack, where you trick a bunch of DNS servers into giving unsolicited responses to the victim.

Alternatively, if the attacker controls a botnet they can just send any type of unsolicited traffic and clog up your pipe or clog up your workstation with requests, pings, etc.

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Sure, that's possible. For a very simple denial of service attack, an attacker just floods the downlink of your internet connection with garbage, thereby preventing any real incoming data from arriving at your computer.

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  • Any clue where I can read more about this specially protecting from it – VarunAgw Apr 24 '14 at 19:04
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    @VarunAgw There are only two real protections against this: Either keep your IP secret (e.g. using Cloudflare for servers) or have more downlink bandwidth than what the attacker can send you. – thejh Apr 24 '14 at 19:08
  • Sorry, Actually I don't understood your answer. That's why I asked for link. Can anyone flood my downlink even if I don't have any HTTP server installed? Also, I am talking about a personal computer with limited bandwidth and speed and not a web server – VarunAgw Apr 24 '14 at 19:22
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    Sure, anyone can send you as many packets as he wants, no matter whether you're running a server or not. I'm unable to find a link to an article about this though, sorry. – thejh Apr 24 '14 at 19:33
  • @thejh I think the link you're looking for is Ping (networking_utility) – Mike Ounsworth May 7 '15 at 0:01

Yes. At a bare minimum, they can perform a simple ping flood or UDP flood attack, where the attacker sends data at a high rate of speed, without worrying about whether or not your computer has a program listening for that data.

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If you are not running any kind of server, your computer and router firewall will reject incoming connections, but this does NOT protect you against a denial of service attack. The reason for this is that by the time the packet reaches your router and your router blocks it, it's already too late - the packet has already essentially reached you and has consumed some of your bandwidth. In other words, the attacker literally does not have to care whether the DoS traffic is being accepted or rejected; as long as the attacker is sending packets at a higher rate than what your connection can accept, your downlink will be saturated.

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