HSRP attack and precaution of LAN Security

HSRP's working principle is not introduced here, I believe we all know.

This is only about the characteristics of HSRP:

1 HSRP virtual out of a brand new IP and MAC address.

2 HSRP's host address version 1 is 224.0.0.2 (all LAN routers), and version 2 's host address is 224.0.0.102 (all HSRP routers).

The HSRP TTL is 1, so it is not possible to achieve a cross network attack.

The default authentication password is plaintext "Cisco"

IPV4 uses UDP's 1985 port, IPV6 is using UDP's 2029 port.

The composing method of virtual Mac:

The correctness of the above is verified by grasping the package below:

One MAC, I set it to 10.

Authentication of two plaintext keys:

Three TTL verification