This document discusses denial of service (DoS) and distributed denial of service (DDoS) attacks. It defines DoS as making a machine or network unavailable to its intended users. DDoS uses other computers to launch the attack. Methods of attack mentioned include ICMP floods, teardrop attacks, and reflected/spoofed attacks. Signs of an attack include slow network performance. The document provides tips for system administrators and users, such as contacting providers and following security best practices, to mitigate attacks.

1. DoS or DDoS Attack
A red eye to Web Services
Presented by...
Tamal Biswas
Kousik Layek
Tridib Biswas

2. Module Index
• What is DoS?
• What is DDoS?
• Recent attack on web.
• Methods of attack.
• Performing DoS attacks.
• How do we know an attack is happening?
• What to do if we are experiencing an attack?
• How do we avoid being part of the problem?
• Conclusion.

3. Denial of Services(DoS)
Its an attack to
make a machine or
network resource
unavailable to its
intended users.

4. Denial of Services(DoS)
Back
Its an attack to
make a machine or
network resource
unavailable to its
intended users.

5. Distributed Denial-of-Service attack
Its an attack to make a
machine or network
resource unavailable to its
intended users
by using others computer.
Network
Back

6. A big-bang of DDoS attack
The internet
around the
whole world was
slowed down on
27th march.
Because that
day DDoS attack
took place with
near about 300
Gbps.
Back

7. Method of attack
• ICMP flood
• Teardrop attacks
• Permanent denial-of-service attacks
• Reflected / Spoofed attack
• Low-rate Denial-of-Service attacks
• Peer-to-peer attacks

8. Some best DoS attack method
• ICMP flood:
– Sends packets to all computer hosts rather than a
specific machine.
• Teardrop attacks:
– Fragmented over-sized pay-loads to be send to
the target machine.
• Permanent denial-of-service attacks:
– It may cause replacement of hardware also.
Back

9. Performing DoS or DDoS Attack
• A wide range of programs are used to launch
DoS-attacks. Some of those are...
Jolt
Bubonic
Targa
Blast
Panther
Crazy Pinger

10. Some best DoS Attack tools
• Jolt:
– Finds exploit vulnerability in windows networking code.
– Consumes 100% CPU time by sending heavy CPU
consuming packets.
• LaTierra:
– It sends TCP packets to more than one port number.
• Nemsey:
– generates random packets with random port number and
floods victim with it.
Back

11. How do we know an attack is happening?
• unusually slow network performance (opening
files or accessing websites)
• unavailability of a particular website
• inability to access any website
• dramatic increase in the amount of spam you
receive in your account

12. A common message after DoS
Back

13. What to do if we are experiencing an
attack?
• contact your network administrators.
• In case of home computer, consider contacting
your internet service provider (ISP).
• Immediatly get disconnected from internet.
Back

14. How do we avoid being part of the
problem?
• Install and maintain anti-virus.
• Install a firewall.
• Configure the firewall to restrict incomming
and outgoing traffic.
• Follow good security practices for distributing
your email address.
• Applying email filters may help you manage
unwanted traffic.
Back

15. Conclusion
• Susceptibility to attacks could be alleviated
with better Internet.
• Don’t leave all the decision making to the
machines.
• Provide ‘intelligent’ support along the path.
• Create “Hardened” networks.

16. Refferences
• http://en.wikipedia.org/wiki/Denial-of-
service_attack

17. Thank you...