6.7

Table Of Contents
VMware standard switches drop any double-encapsulated frames that a
virtual machine attempts to send on a port configured for a specific VLAN.
Therefore, they are not vulnerable to this type of attack.
Multicast brute-force
attacks
Involve sending large numbers of multicast frames to a known VLAN
almost simultaneously to overload the switch so that it mistakenly allows
some of the frames to broadcast to other VLANs.
VMware standard switches do not allow frames to leave their correct
broadcast domain (VLAN) and are not vulnerable to this type of attack.
Spanning-tree attacks Target Spanning-Tree Protocol (STP), which is used to control bridging
between parts of the LAN. The attacker sends Bridge Protocol Data Unit
(BPDU) packets that attempt to change the network topology, establishing
themselves as the root bridge. As the root bridge, the attacker can sniff the
contents of transmitted frames.
VMware standard switches do not support STP and are not vulnerable to
this type of attack.
Random frame attacks Involve sending large numbers of packets in which the source and
destination addresses stay the same, but in which fields are randomly
changed in length, type, or content. The goal of this attack is to force
packets to be mistakenly rerouted to a different VLAN.
VMware standard switches are not vulnerable to this type of attack.
Because new security threats develop over time, do not consider this an exhaustive list of attacks.
Regularly check VMware security resources on the Web to learn about security, recent security alerts,
and VMware security tactics.
Secure vSphere Distributed Switches and Distributed Port
Groups
Administrators have several options for securing a vSphere Distributed Switches in their vSphere
environment.
Procedure
1 For distributed port groups with static binding, disable the Auto Expand feature.
Auto Expand is enabled by default in vSphere 5.1 and later.
To disable Auto Expand, configure the autoExpand property under the distributed port group with the
vSphere Web Services SDK or with a command-line interface. See the vSphere Web Services SDK
documentation.
2 Ensure that all private VLAN IDs of any vSphere Distributed Switch are fully documented.
vSphere Security
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