DoS Attacks

DoS Attacks

By ghost | 6494 Reads |

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Denial of Service Attacks

I decided to write this because it's the most common used attack methods and people don't really seem to know what they are and how they're performed.

So I'll just list the well-known ones right here:

• DDoS

Distributed Denial of Service. Simply make a lot of computers send heaps of data to flood a server.

• IGMP Attack

Based on an error in the Internet Group Management Protocol which is used by routers to decide whether or not users are allowed on a certain subnet. The protocol usually sends out multicasting packets which aren't all that big. With an IGMP attack you send much bigger packets so that the protocol can't handle them. Consequence? Blue screen of death and a terminated network connection.

• SYN Flooding

Uses the Three Way Handshake by constantly connecting with the server without disconnecting. There's no stopping this one.

• Finger attack

Only to be used in a unix network. Costs the server a lot of HDD space, memory and bandwith which makes it crash. It's simply repeatedly calling finger:

finger @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@hostname

• Teardrop attack

When a way too large packet is sent via the Internet Protocol (IP) it splits it up into fragments. Every fragment packet has an offset to the beginning of another packet so that they can be put together again by the next system it will reach. With the teardrop attack, the attacker puts a confusing offset value in on of the fragments (not the first). Most of the time this causes the system to crash.

• ICMP Flood

Repeatedly sending packets to the server making it crash (best done distributed). Make a batch file with the following lines:

:loop ping [hostname] -f goto loop

Change [hostname] ;)

• Smurf attack

Same as ping of death, but with a spoofed return address.

• Fraggle attack:

Same as Smurf attack, but without using another victim to spoof the return address.

• trin00

http://staff.washington.edu/dittrich/misc/trinoo.analysis has to do with solaris.

Now, as you can see DoS attacks don't have to be stupid/dumb (skiddies perform them a lot though). I personally think the Teardrop attack is quite original. :-)

HvT