In which type of Layer 2 attack does an attacker broadcast BDPUs with a lower switch priority?

A.
MAC spoofing attack

B.
CAM overflow attack

C.
VLAN hopping attack

D.
STP attack

Explanation:
http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/white_paper_c11_605972.ht
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Introduction
The purpose of this paper is to identify how easily the Spanning-Tree Protocol (STP) can be
compromised to allow eavesdropping in a switched corporate environment and how to mitigate this
vulnerability using L2 security features that are available on the Cisco® Catalyst® 6500.
The Spanning Tree Protocol (STP) Man in The Middle (MiTM) attack compromises the STP “Root
Bridge” election process and allows a hacker to use their PC to masquerade as a “Root Bridge,” thus
controlling the flow of L2 traffic. In order to understand the attack, the reader must have a basic
understanding of the “Root Bridge” Election process and the initial STP operations that build the
loop free topology. Therefore, the first section of this document, Overview of the STP Root Bridge
Election Process, will be devoted to providing a simplified explanation of 802.1d STP operations as it
pertains to understanding the STP MiTM attack. If you require a more comprehensive overview of
STP, please review the LAN Switching Chapter of the Cisco
Catalyst 6500 Configuration Guide on Cisco.com.