Question

Consider a distributed variant of the attack in the previous problem. Assume the attacker has compromised a number of broadband-connected residential PCs to use as zombie systems. Also assume each such system has an average uplink capacity of 512 kbps.

* a. What is the maximum number of 500-byte ICMP echo request (ping) packets a single zombie PC can send per second?

* b. How many such zombie systems would the attacker need to flood a target organization using a 30-Mbps link? A 100-Mbps link? A 1-Gbps link?

Answer 1

ANSWER-:

given,

Uplink capacity of zombie = 512 kbps = 512X2^10

= 512X1024 = 524288 bits per second

a. 500 byte message = 500X8 = 4000 bits

# of packet = Uplink capacity of zombie(W) / message(P)

                 = 524288 / 4000 = 131.072 = 132 packets per second

b.

# of zombies = capacity of target system / capacity if zombies

(i)- flood 30 Mbps : 30 Mbps / 512 kbps = 30x2^20 / 512x2^10 = 60 zombies

  

(ii)- flood 100 Mbps : 100 Mbps / 512 kbps = 100x2^20 / 512x2^10 = 200 zombies

                                                         

(iii)- flood 1 Gbps : 1 Gbps / 512kbps = 1x2^30 / 512x2^10 = 2048 zombies

2^10 = 1024

1 byte = 8 bits

1 Kbps = 2^10 bits per second

1 Mbps = 2^10 Kbps = 2^10x2^10 bits per second = 2^20 bits per second

1 Gbps = 2^10 Mbps = 2^10x2^10 Kbps = 2^10x2^10x2^10 bits per second = 2^30 bits per second