| V-62155 | High | The layer 2 switch must uniquely identify all network-connected endpoint devices before establishing any connection. | Controlling LAN access via 802.1x authentication can assist in preventing a malicious user from connecting an unauthorized PC to a switch port to inject or receive data from the network without detection. |
| V-62195 | Medium | The layer 2 switch must enable Unidirectional Link Detection (UDLD) to protect against one-way connections. | In topologies where fiber optic interconnections are used, physical misconnections can occur that allow a link to appear to be up when there is a mismatched set of transmit/receive pairs. When... |
| V-62197 | Medium | The layer 2 switch must have all trunk links enabled statically. | When trunk negotiation is enabled via Dynamic Trunk Protocol (DTP), considerable time can be spent negotiating trunk settings (802.1q or ISL) when a node or interface is restored. While this... |
| V-62193 | Medium | The layer 2 switch must implement Rapid STP where VLANs span multiple switches with redundant links. | Spanning Tree Protocol (STP) is implemented on bridges and switches to prevent layer 2 loops when a broadcast domain spans multiple bridges and switches and when redundant links are provisioned to... |
| V-62199 | Medium | The layer 2 switch must only allow a maximum of one registered MAC address per each user-facing or untrusted access port. | Limiting the number of registered MAC addresses on a switch access port can help prevent a Content Addressable Memory (CAM) table overflow attack. This type of attack lets an attacker exploit the... |
| V-62169 | Medium | The layer 2 switch must provide the capability for authorized users to remotely view, in real time, all content related to an established user session from a component separate from the layer 2 switch. | Without the capability to remotely view/hear all content related to a user session, investigations into suspicious user activity would be hampered. Real-time monitoring allows authorized personnel... |
| V-62065 | Medium | The layer 2 switch must be configured to disable non-essential capabilities. | A compromised switch introduces risk to the entire network infrastructure as well as data resources that are accessible via the network. The perimeter defense has no oversight or control of... |
| V-62165 | Medium | The layer 2 switch must be configured to fail securely in the event of an operational failure. | If the switch fails in an unsecure manner (open), unauthorized traffic originating externally to the enclave may enter or the device may permit unauthorized information release. Fail secure is a... |
| V-62167 | Medium | The layer 2 switch must provide the capability for authorized users to select a user session to capture. | Without the capability to select a user session to capture/record or view/hear, investigations into suspicious or harmful events would be hampered by the volume of information captured. The volume... |
| V-62161 | Medium | The layer 2 switch must authenticate all VLAN Trunk Protocol (VTP) messages with a hash function using the most secured cryptographic algorithm available. | VLAN Trunk Protocol (VTP) provides central management of VLAN domains, thus reducing administration in a switched network. When configuring a new VLAN on a VTP server, the VLAN is distributed... |
| V-62163 | Medium | The layer 2 switch must manage excess bandwidth to limit the effects of packet flooding types of denial of service (DoS) attacks. | Denial of service is a condition when a resource is not available for legitimate users. Packet flooding DDoS attacks are referred to as volumetric attacks and have the objective of overloading a... |
| V-62211 | Medium | The layer 2 switch must have the native VLAN assigned to an ID other than the default VLAN for all 802.1q trunk links. | VLAN hopping can be initiated by an attacker who has access to a switch port belonging to the same VLAN as the native VLAN of the trunk link connecting to another switch that the victim is... |
| V-62185 | Medium | The layer 2 switch must have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs. | DAI intercepts Address Resolution Protocol (ARP) requests and verifies that each of these packets has a valid IP-to-MAC address binding before updating the local ARP cache and before forwarding... |
| V-62183 | Medium | The layer 2 switch must have IP Source Guard enabled on all user-facing or untrusted access switch ports. | IP Source Guard provides source IP address filtering on a Layer 2 port to prevent a malicious host from impersonating a legitimate host by assuming the legitimate host's IP address. The feature... |
| V-62181 | Medium | The layer 2 switch must have DHCP snooping for all user VLANs to validate DHCP messages from untrusted sources as well as rate-limit DHCP traffic. | In an enterprise network, devices under administrative control are trusted sources. These devices include the switches, routers, and servers in the network. Host ports and unknown DHCP servers are... |
| V-62179 | Medium | The layer 2 switch must have Unknown Unicast Flood Blocking (UUFB) enabled. | Access layer switches use the Content Addressable Memory (CAM) table to direct traffic to specific ports based on the VLAN number and the destination MAC address of the frame. When a router has an... |
| V-62171 | Medium | The layer 2 switch must authenticate all network-connected endpoint devices before establishing any connection. | Without authenticating devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity.
For distributed architectures (e.g., service-oriented architectures),... |
| V-62177 | Medium | The layer 2 switch must have STP Loop Guard enabled on all non-designated STP switch ports. | The Spanning Tree Protocol (STP) loop guard feature provides additional protection against STP loops. An STP loop is created when an STP blocking port in a redundant topology erroneously... |
| V-62175 | Medium | The layer 2 switch must have BPDU Guard enabled on all user-facing or untrusted access switch ports. | If a rogue switch is introduced into the topology and transmits a Bridge Protocol Data Unit (BPDU) with a lower bridge priority than the existing root bridge, it will become the new root bridge... |
| V-62205 | Medium | The layer 2 switch must have the default VLAN pruned from all trunk ports that do not require it. | The default VLAN (i.e., VLAN 1) is a special VLAN used for control plane traffic such as Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN Trunking Protocol (VTP), and Port... |
| V-62207 | Medium | The layer 2 switch must not use the default VLAN for management traffic. | Switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with directly connected switches using Spanning-Tree Protocol (STP), Dynamic Trunking Protocol (DTP), VLAN... |
| V-62201 | Medium | The layer 2 switch must have all disabled switch ports assigned to an unused VLAN. | It is possible that a disabled port that is assigned to a user or management VLAN becomes enabled by accident or by an attacker and as a result gains access to that VLAN as a member. |
| V-62203 | Medium | The layer 2 switch must not have the default VLAN assigned to any host-facing switch ports. | In a VLAN-based network, switches use the default VLAN (i.e., VLAN 1) for in-band management and to communicate with other networking devices using Spanning-Tree Protocol (STP), Dynamic Trunking... |
| V-62209 | Medium | The layer 2 switch must have all user-facing or untrusted ports configured as access switch ports. | Double encapsulation can be initiated by an attacker who has access to a switch port belonging to the native VLAN of the trunk port. Knowing the victim's MAC address and with the victim attached... |
| V-95879 | Low | The layer 2 switch must have Storm Control configured on all host-facing switch ports. | A traffic storm occurs when packets flood a LAN, creating excessive traffic and degrading network performance. Traffic storm control prevents network disruption by suppressing ingress traffic when... |
| V-62213 | Low | The layer 2 switch must not have any switch ports assigned to the native VLAN. | Double encapsulation can be initiated by an attacker who has access to a switch port belonging to the native VLAN of the trunk port. Knowing the victim’s MAC address and with the victim attached... |
| V-95881 | Low | The layer 2 switch must have IGMP or MLD Snooping configured on all VLANs | IGMP and MLD snooping provides a way to constrain multicast traffic at Layer 2. By monitoring the IGMP or MLD membership reports sent by hosts within a VLAN, the snooping application can set up... |
| V-62173 | Low | The layer 2 switch must have Root Guard enabled on all switch ports connecting to access layer switches and hosts. | Spanning Tree Protocol (STP) does not provide any means for the network administrator to securely enforce the topology of the switched network. Any switch can be the root bridge in a network.... |
