This design, shown in Figure
, represents a
large data center within a single enterprise. However, the need to segregate
traffic as well as data for various groups or departments within the enterprise
is reflected by the separation of the data center into security zones. This can
be accomplished securely through the use of VLANs within the data center,
however, there are considerations which must be evaluated regarding some of the
potential vulnerabilities. In Figure
, the two
switches have a trunk between them represented by the solid green line carrying
all of the VLAN traffic between the switches.
Vulnerabilities
The primary layer 2 vulnerabilities of this
design include the following:
- MAC spoofing, within VLANs
- CAM table overflow, through per VLAN traffic flooding
- VLAN hopping
- STP attacks
Mitigation
If the security zones are small enough, use port
security to help mitigate CAM table overflow vulnerabilities as well as the MAC
spoofing vulnerability. Additionally, mitigation of VLAN hopping can be
accomplished by following the VLAN best practices outlined in this module. If
necessary, deploy 802.1x authentication to prevent unauthorized access to each
of the security zones from an attacker who may physically connect to a switch
in the design. Another possible mitigation method would be to add a firewall
within the design, or add a Layer 3 switch with an integrated firewall as shown
in Figure
. The
firewall enforces additional Layer 3 traffic segregation. As with the previous
cases, the switches must be managed as securely as possible and tested on a
regular basis.