This results in a denial of service to the legitimate host on the network. In a DHCP starvation attack, the attacker requests all of the available DHCP addresses. It is possible to attack DHCP servers by causing denial of service in the network or by impersonating the DHCP server. DHCP Attacksĭynamic Host Configuration Protocol (DHCP) is not a datalink protocol but solutions to DHCP attacks are also useful to thwart Layer 2 attacks.ĭHCP is used to dynamically allocate IP addresses to computers for a specific time period. Thus, the attacker now receives all the frames which were actually destined only for the target host. Now all data frames intended for the targeted host are sent to the attacker’s switch port and not to the target host. Switch is fooled to believe that the target host is on port, on which actually an attacker is connected.
Mac address flooding attack mac#
The attacker floods the switch with forged ARP frames with the target host’s MAC address as the source address. The port stealing attack exploits this ability of the switches. When a switch receives traffic from a port with a MAC source address, it binds the port number and that MAC address. Port StealingĮthernet switches have the ability to learn and bind MAC addresses to ports. The attacker who is on the same network, now receives all the frames which were destined only for a specific host. Once CAM is flooded, the switch goes into hub-like mode and starts broadcasting the traffic that do not have CAM entry.
In the MAC flooding attack, the attacker floods the switch with MAC addresses using forged ARP packets until the CAM table is full. MAC FloodingĮvery switch in the Ethernet has a Content-Addressable Memory (CAM) table that stores the MAC addresses, switch port numbers, and other information. Often the attack is used to launch other attacks such as man-in-the-middle, session hijacking, or denial of service. The process of modifying a target host’s ARP cache with a forged entry known as ARP poisoning or ARP spoofing.ĪRP spoofing may allow an attacker to masquerade as legitimate host and then intercept data frames on a network, modify or stop them. Since ARP is a stateless protocol, every time a host gets an ARP reply from another host, even though it has not sent an ARP request, it accepts that ARP entry and updates its ARP cache. The table holds the IP address and associated MAC addresses of other host on the network. The other host that owns the IP address sends an ARP reply message with its physical address.Įach host machine on network maintains a table, called ‘ARP cache’. When a host machine needs to find a physical Media Access Control (MAC) address for an IP address, it broadcasts an ARP request. The most common attacks are − ARP SpoofingĪddress Resolution Protocol (ARP) is a protocol used to map an IP address to a physical machine address recognizable in the local Ethernet. Security Concerns in Data Link Layerĭata link Layer in Ethernet networks is highly prone to several attacks. Our discussion will be focused on Ethernet network. In this chapter, we will discuss security problems at Data Link Layer and methods to counter them. This can open the network to a variety of attacks and compromises. However, one area generally left unattended is hardening of Data Link layer. Many organizations incorporate security measures at higher OSI layers, from application layer all the way down to IP layer. Several methods have been developed to provide security in the application, transport, or network layer of a network. We have seen that rapid growth of Internet has raised a major concern for network security.
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