denial of service attacks ddos ICMP flood and Teardrop flood
- ICMP Flood :
An ICMP Flood or Ping flood or a Smurf Attack is one of the most popular ways of carrying out DoS attacks on the internet. In this attack, the attacker sends large amounts of ICMP packets (or sometimes by sending oversized packets) in order to crash the TCP/IP stack (TCB) of the server machine.
- Teardrop Attack :
This attack utilizes a bug in the OS itself for causing a Denial of Service. This attack usually affected Windows 3.1, 95 and NT machines and also Linux versions previous to 2.0.32 and 2.1.63. The bug causes the TCP/IP fragmentation re-assembly code to improperly handle overlapping IP fragments. The packets are forged to overlap over each other, where the host tries to reassemble them causing a slowdown in the network performance.
These were some of the important methods of performing Denial of Service Attacks. However, the methods are not limited to only these three. The student should go ahead and read for more methods of performing DoS Attacks.
With the increase in tools approach, these days Denial of Service attacks could be easily performed by any script kiddy. One of such tools is LOIC or Low Orbit Ion Cannon. It is an open source tool, coded in C# and designed for network stress testing by penetration testers. However, this tool has been recently used by a large group of hackers, for carrying out DoS attacks (or DDoS when used by multiple persons) against big corporations, most of them landing behind the bars finally.