A lab in which the execution and prevention of layer 2 attacks are detailed. Device configurations and the ways to execute attacks are detailed in the corresponding folders.
Background information on lab concepts can be found here: https://101zh.github.io/networking/
The purpose of this lab is to perform three layer 2 attacks to understand them. Then to discover how to prevent and mitigate these attacks. This lab’s purpose is the demonstrate practices that can prevent a network from being attacked from layer 2.
Execution and prevention of attacks can be found here:
In this lab, three layer 2 attacks were performed: MAC flooding, DHCP starvation & VLAN hopping, and ARP spoofing. These attacks were performed on a common office network with an access point, a switch, and a router. This report details how to perform these attacks as well as mitigate each of these attacks in their respective sections.
More details on the configuration of this topology can be found here: https://github.com/101zh/StandaloneAccessPointLab
Note: a VLAN other than VLAN 1 should be used as the native VLAN to further mitigate VLAN hopping attacks, but it is not configured here.
- interface {type slot/port}
- switchport port-security maximum [number-of-addresses]
- Sets the maximum number of mac-addresses a port can learn
- switchport mode access
- Sets the interface to a non-trunking VLAN layer 2 interface
- switchport access vlan [vlan-number]
- Sets the VLAN the interface operates in for access mode
- ip dhcp snooping trust
- Configures the specified interface to be a trusted interface. By default, interfaces are not trusted. Usually, interfaces that are configured as trusted are the interface closest to the DHCP server.
- switchport port-security
- Enables port security on the specified interface
- switchport port-security aging time [time]
- Sets the time for which a mac-address is remembered as a secure address.
- switchport port-security aging type {absolute | inactivity}
- Sets the type of aging the port will use. The type of inactivity sets it so that the mac-addresses are forgotten after a period of inactivity specified by the aging time. The type of absolute, which is default, will forget a mac-address in the specified aging time after it was learned.
- switchport port-security mac-address {mac-addr | sticky}
- Specifies the secure mac-addresses. Addresses can be statically set or by using the keyword “sticky,” mac-addresses can be dynamically learned.
- switchport nonegotiate
- Statically sets the specified interface to not use Dynamic Trunking Protocol (DTP)
- switchport port-security maximum [number-of-addresses]
- ip dhcp snooping
- Enables DHCP snooping globally in the switch
- ip dhcp snooping verify mac-address
- Configures the switch to verify that the mac-address learned on the port matches the mac-address field in DHCP packets
- ip arp inspection vlan [vlan-number1 … vlan-number8]
- Enables dynamic ARP inspection (DAI) on the specified VLANs
- ip arp inspection validate {dst-mac | src-mac}
- Validates the ARP frames that go through the switch. The two options configure DAI to compare the ethernet mac-addresses of the destination and source to the ARP body, respectively.
- ip arp gratuitous none
- Rejects gratuitous ARPs.
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