Can anybody tell me what are DoS and DDoS attacks and what are its variants? How are they originated. I would be really thankfull
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Can anybody tell me what are DoS and DDoS attacks and what are its variants? How are they originated. I would be really thankfull
DOS - Denial of Service
Thats when one computer is used to overwhelm another till it has crashed.
DDOS - Distributed Denial of Service
Thats when multiple computers are used to target one computer.
Basically the DOS attack is an attempt to overload a computer with information that it cannot accept anymore legit requests. Alot of the DOS attacks you see are aimed @ web servers and what not. I've seen DOS attacks from 45KB a sec to over 900Mb a sec @ one computer. As you might imagine having all that information attacking one computer can overwhelm it very quickly.
DOS attacks can also be used to overwhelm networks. If you have a 100Mbps network it won't take much over 95Mbps to make your network sluggishly slow. A few more Mbps and your network is down.
DoS definition: Denial of Service. An attack that is not virus-based, but a action preformed by crackers to prevent or deny legitimate users access to a computer. This can include a flood of information that overloads what a server can handle, and thus causing it to lag or crash; to even forcing an FTP account to lock down because someone deliberatlly gave it the wrong login password so many times that the system shut down that users account.
DoS example:
Smurf DoS Attack - http://securityresponse.symantec.com...os.attack.html
DDoS definition: Distributed Denial of Service. Similar to a DoS, but on a MUCH larger scale. Distributed Denial of Service attacks are done from multiple attack servers (or even home computers that are infected with a trojan/virus), which are remotely controllable by a cracker. All of those computers combined together launch a DoS upon a target. Think of it like Vultron when all of the robots came together to form a more powerful robot. Same concept, but a stronger and more deadly DoS.
DoS example:
Trojan Zombies that remain in someone's computer silently, until the remote user activates this. this attack was used in bringing down yahoo.com when thousands of zombied computers pinged yahoo.com over and over until the server couldn't handle the load and crashed out.
How can we send a large amount of data to particular network untill or unless are autorized to do so.Quote:
this can include a flood of information that overloads what a server can handle, and thus causing it to lag or crash;
A few ways:Quote:
How can we send a large amount of data to particular network untill or unless are autorized to do so.
1. Access a webpage over and over and over and over and over and over again.
2. Use the ping command to send constant ICMP-based data over and over and over again
3. Send "garbage" data packages (to put it in non techincal terms). Even if it is garbage, the computer target still has to take the time to register what you are sending it, verify it as junk, and then tell you that it was rejected. Do that over and over again. There are a few ways to send junk data packages, but most involve crafting your own UDP/TCP/ICMP/IP packets.
Quote:
Originally posted here by guardian alpha
A few ways:
1. Access a webpage over and over and over and over and over and over again.
2. Use the ping command to send constant ICMP-based data over and over and over again
3. Send "garbage" data packages (to put it in non techincal terms). Even if it is garbage, the computer target still has to take the time to register what you are sending it, verify it as junk, and then tell you that it was rejected. Do that over and over again. There are a few ways to send junk data packages, but most involve crafting your own UDP/TCP/ICMP/IP packets.
Good info, just a subnote to this.
Most servers/routers are equiped with filters to deny these type of attacks, and will usually dispense with repetitive packets. On a good day it will result in no down time.
P:
Denial of service is simply that. Your denying access to web-services and its not always associated with flooding, ya morons.
I take it you didn't read the very first line of my post here? No reason to resort to calling people 'morons' either.Quote:
Denial of service is simply that. Your denying access to web-services.
Quote:
Most servers/routers are equiped with filters to deny these type of attacks, and will usually dispense with repetitive packets. On a good day it will result in no down time.
this is where DDoS comes into play, sure the router blocks the packets after a bit, but if you execute successfully you can drop a router in seconds. not to mention the fact that many people doing these attacks first crack the router and then attacka node within the network itself or an even more important router. AND once you crack a router or node on a network the other routers know that its an internal IP and allow the traffic. so it is very possible and somewhat easy to launch a DDoS attack, especially on a smaller scale like a school or small business.
Wouldn't in theory there be more stress on a router trying to filter packets that are malformed or fragmented, than if it wasn't? And thus, do you think that a stateful router blocking advanced packet configurations is going to drop(crash/lag) faster than it the router wasn't worried about it?Quote:
sure the router blocks the packets after a bit, but if you execute successfully you can drop a router in seconds
Thanks to you all buddies for your responses.
Can you tell me how can I hang my friend's pc whose on our network of 6 pcs.
I can't do it by just pinging.
It generallty isn't a good idea to do that, to even your friend, unless you have permission to specifically test it out their computer.
In certain parts of the world, it's also considered illegal since it is a form of 'cyber-attack'
Ask your friend if you can test on his computer (or test on one of your own) before preforming any sort of DoS on him. If you don't own these computers, say they are school or library property, then don't even think about attempting it in the first place.
Yes, I have the permission to access my friend's computer. I just want to check If I can do that.
In my experience... I just made a private network and flooded my roommate to test vulnerablilties and such. Its safe that way.. just get behind a HUB/Router and you can do what ever you want without being concerned about the law, as long as you keep it in your network. Cause if you were to DOS your freind who is on Road Runner or COX, you wouldnt be flooding him... you would be flooding his providor. You see... setup a private LAN and knock yourself out... :)
I have my private network which is not et al connected to internet. I am doing this just for knowledge. By the way nobody has told me clearly how to flood the other computer in my network.Quote:
... you can do what ever you want without being concerned about the law, as long as you keep it in your network. Cause if you were to DOS your freind who...
anybody please...
Regards,
Navdeep
Not sure about some of the DOS tools out there, I guess they do exist, but I've put firewall CPU's under stress by sending lots of ICMP packets with a large buffer size, I was doing it on a course the other week. Then used Cisco Pix Device Manager to watch the CPU on this particular firewall go through the roof.
So you could have a batch file with 'ping 192.168.0.10 -l 65500' and just keep on double clicking it, this will eventually put a test host on a test network under some stress.
James.
My dear Goz(James),Quote:
...a batch file with 'ping 192.168.0.10 -l 65500' and just keep on double clicking it, this will eventually put a test host on a test network under some stress...
Mine network is not a busy one and there are just 5 pcs ( 3 P4-2 Gigs,1 Celeron-1.7 gigs and 1-AMD 2.4 gigs) and hence cannot be simply downed by just pinging. How so ever pinging is done.
Gi'me some other solution please.
http://www.cotse.com/dos.htm <-- use at your own risk.
Thank you MsMittens for your kind help and especially for that link.
You can also try using stress testing tools to find out how much trafffic your server/machine can handle. This could help you figure out if it is the network or server that is in DOS, (where is the weak link??).
This will answer the question 'At which point does a lot of traffic become a DOS/DDOS? and what fails?"
F1Fan
Now since I have learned the basics of DOS and DDOS attacks with the help of valuable information provided by you guys/girls. Thanks again.
Now,what are all the possible ways of preventing these attacks. sorry for troubling you again!!
but this would help me understanding these attacks more closely.
Regards,
Navdeep
You'd be surprised. If you were targeting just the one host you can certainly affect it's performance. The link provided by the other poster is probably more what you are after though.Quote:
Originally posted here by gess~da~devil
My dear Goz(James),
Mine network is not a busy one and there are just 5 pcs ( 3 P4-2 Gigs,1 Celeron-1.7 gigs and 1-AMD 2.4 gigs) and hence cannot be simply downed by just pinging. How so ever pinging is done.
Gi'me some other solution please.