Easy 802.1Q VLAN Hopping
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Frogger - VLAN Hopping

Simple VLAN enumeration and hopping script.

Released as open source by NCC Group Plc - http://www.nccgroup.com/

Developed by Daniel Compton, daniel dot compton at nccgroup dot com


Released under AGPL see LICENSE for more information


git clone https://github.com/nccgroup/vlan-hopping.git

How To Use


Run as root.


  • Sniffs out CDP packets and extracts (VTP domain name, VLAN management address, Native VLAN ID and IOS version of Cisco devices)
  • It will enable a DTP trunk attack automatically
  • Sniffs out and extracts all 802.1Q tagged VLAN packets within STP packets and extracts the unique IDs.
  • Auto arp-scans the discovered VLAN IDs and auto tags packets and scans each VLAN ID for live devices.
  • Auto option to auto create a VLAN interface within the found network to connect to that VLAN.


Tested on Backtrack 5 and Kali.

  • Notes for VMware. VLAN hopping generally (not just this script) can have issues within VMware if running the VM within Windows with certain Intel drivers. The Intel drivers strip off the tags before it reaches the VM. Either use an external USB ethernet card such as a DLink USB 2.0 DUB-E100 (old model 10/100 not gigabit) or boot into Backtrack nativiely from a USB stick. Intel has published a registry fix, to work on some models: http://www.intel.com/support/network/sb/CS-005897.htm - adding "MonitorMode" 1 to the registry does resolve the issue.

Screen Shot



Change Log

  • Version 2.0 - (Coming soon) will support Cisco ISL encapsulation.
  • Version 1.8 - Added VMware detection and Intel NIC detection to assist with common problems within VMware.
  • Version 1.7 - New look, bug fixes and speed improvements.
  • Version 1.5 - Official release.