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How to block Internet sharing by MacBook on Cisco Switches Cisco Vulnerability

Hi everyone.


I have a issue, on my LAN we found a vulnerability, the MAC laptop (MacBook Pro) had a sharing internet  featuring. using Ethernet cable connected and you can share internet ussing AirPort to the other devices, you can configure the MAC as Access Point and make a NAT on the network.


I applied the port-security using max 2 mac address and switchport protect and spanning-tree bpduguard and traffic still passing. If you analyze the traffic you will only see the ip Ethernet cable, even apply the dhcp snoop give a IP address on devices connect to the MacBook.


Configuring port:


interface GigabitEthernet1/0/2
 description desk Mariano
 switchport access vlan 21
 switchport mode access
 switchport protected
 switchport block unicast
 switchport voice vlan 621
 switchport port-security maximum 2
 switchport port-security
 switchport port-security violation restrict
 switchport port-security mac-address sticky
 switchport port-security mac-address sticky 10dd.b1d7.e1a2
 switchport port-security mac-address sticky a40c.c394.08ef vlan voice
 logging event spanning-tree
 logging event status
 srr-queue bandwidth share 10 10 60 20
 srr-queue bandwidth shape  10  0  0  0
 queue-set 2
 udld port aggressive
 mls qos trust device cisco-phone
 mls qos trust cos
 auto qos voip cisco-phone
 storm-control unicast level 1.00
 storm-control action shutdown
 spanning-tree portfast
 spanning-tree bpduguard enable


At this moment MacBook Pro share a 3 devices, and the local port only see 2 mac address (The MacBook and IP Telephony).


          Mac Address Table

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
  21    10dd.b1d7.e1a2    STATIC      Gi1/0/2
 621    a40c.c394.08ef    STATIC      Gi1/0/2
Total Mac Addresses for this criterion: 2


Pls helpus, any body can see the problem.



Best Regards.


Frequent Contributor

Not sure if there is any feature to prevent ad-hoc wireless networks originated from a user machine  from a Cisco Switch stand point of view, generally the User IT dept will create a GPO to disable ad-hoc networking on user wnic's or you have the wireless dept that keeps an eye on the any rogue AP's popping up in your network.

I am sure the Wireless Controllers now are capable of switchport tracing for rogue AP's and err-disable them as well.


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