Question

If an attacker wants to disrupt a network service such as DHCP (dynamic host configuration protocol) why would he or she choose a DHCP starvation attack? What is the motive behind such an attack? Moreover, how do we mitigate against such an attack?

Answer 1

DHCP starvation attack:

It’s a denial of service attack, an attacker sends forged DHCP requests to the server and leases all the available IP’s thus the legitimate clients will not get an IP assigned; or the Attacker may send bogus request/replies luring the client to connect to attacker’s machine instead of valid DHCP server

why he or she choose:

DHCP is the reason for which we all get the logical addresses of our Machines aka IP Addresses. So, in a DHCP Starvation Attack, an Attacker Broadcasts large Number of DHCP Requests Packets with some sort of spoofed MAC Address (Physical Address of the Machine provided by the Network Interface Card) with the help of tools like Yersinia and DHCP Rogue Server. If enough requests are sent, the DHCP Server will start to respond to all those Requests Packets and the Attacker will be able to Exhaust or Consume all the available IP Addresses available to the DHCP Server for a particular period of time.

motivation behind and how to mitigate attacks:

DHCP starvation attack is an attack that targets DHCP servers whereby forged DHCP requests are crafted by an attacker with the intent of exhausting all available IP addresses that can be allocated by the DHCP server. Under this attack, legitimate network users can be denied service. In this paper, we describe the seriousness of the attack and survey and evaluate existing solutions designed to mitigate such an attack. In addition, we propose a novel mitigation solution. Our solution overcomes the limitations of existing solutions in terms of performance, effectiveness, and flexibility. Our solution is based on dynamic fair allocation of IP addresses and is suitable for unshared and shared (wireless) access networks. We study and analyze the proposed mitigation technique through numerical examples and simulations. Furthermore, simulation results show that our proposed solution is far superior in mitigating DHCP starvation attack when compared to other existing techniques such as fixed allocation and DHCP request rate detection.

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