VLANhoppinguhkat

VLAN hopping is a network security vulnerability that allows an attacker to gain unauthorized access to traffic on other virtual local area networks (VLANs) that they are not supposed to have access to. This can be achieved through various techniques, often by exploiting the way network switches handle VLAN tagging.

One common method is switch spoofing, where an attacker configures their machine to act like a switch. By sending special VLAN trunking protocol (VTP) messages, they can trick a legitimate switch into believing their machine is part of the trunking infrastructure, thereby allowing them to access all VLANs on that trunk. Another technique involves exploiting the Dynamic Trunking Protocol (DTP) by sending DTP negotiation packets to a switch port that is configured to auto-trunk. This can cause the port to become a trunk port, granting the attacker access to multiple VLANs.

A more advanced attack involves crafting packets with double VLAN tags. When such a packet arrives at a switch, the switch may strip off the outer tag and forward the packet based on the inner tag. If the attacker can manipulate the inner tag to match a different VLAN, they can effectively send traffic to that VLAN.

The consequences of a successful VLAN hopping attack can be severe, including data breaches, the interception of sensitive information, and the ability to launch further attacks within the compromised network. Network administrators can mitigate these risks by disabling DTP on user-facing ports, configuring switch ports to be explicitly access or trunk ports rather than using auto-negotiation, and implementing strict access controls and monitoring.