VLAN Hopping Attack

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VLAN hopping is an attack designed to send traffic to a VLAN other than the one the host system is in.

• exploits the default VLAN feature of 802.1Q
  • default VLANs are designed to provide compatibility with non-VLAN capable switches
  • attacker, using device in the default VLAN, crafts a frame with two VLAN tag headers
  • first trunk switch to inspect the frame strips the first header and frame gets forwarded to the target VLAN
  • such attack can only send packets one way
    • but could be used to perform a DoS attack against a host on a different VLAN
• can be launched by attaching a device that spoofs the operation of a switch to the network and negotiating the creation of a trunk port
  • as a trunk port, the attacker device will receive all inter-VLAN traffic
• Mitigate by:
  • using separate physically switches

Spanning Tree Protocol Manipulation Attack

• STP is normally configured on a network with several switches
• primary purpose is to prevent switching loops
• to make STP work, a single switch is designated as the root bridge
• if attacker becomes root bridge, they are able to see a variety of frames that normally would not see
• to perpetrate this attack,
  • attacker inserts their switch into the tree and manipulates it to appoint their switch as the root bridge
  • then can use a sniffer to collect data