Cisco IOS Switch L2S Security Technical Implementation Guide

Overview

Version	Date	Finding Count (26)			Downloads
1	2020-05-07 2021-03-26 2021-06-02 2021-06-02 2022-09-12 2022-09-12 2022-09-12 2022-09-12 2022-09-12 2023-09-14 2023-09-14 2023-09-14 2024-06-06	CAT I (High): 1	CAT II (Med): 21	CAT III (Low): 4	Excel	JSON	XML

STIG Description
This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DoD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil.

Available Profiles

Classified	Public	Sensitive
I - Mission Critical Classified	I - Mission Critical Public	I - Mission Critical Sensitive	II - Mission Support Classified	II - Mission Support Public	II - Mission Support Sensitive	III - Administrative Classified	III - Administrative Public	III - Administrative Sensitive

Findings (MAC III - Administrative Classified)

Finding ID	Severity	Title	Description
V-101113	High	The Cisco 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-101159	Medium	The Cisco 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-101155	Medium	The Cisco 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-101157	Medium	The Cisco 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-101151	Medium	The Cisco 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-101153	Medium	The Cisco 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-101111	Medium	The Cisco 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-101119	Medium	The Cisco switch must be configured 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-101115	Medium	The Cisco switch must authenticate all VLAN Trunk Protocol (VTP) messages with a hash function using the most secured cryptographic algorithm available.	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 through all switches in...
V-101117	Medium	The Cisco 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-101133	Medium	The Cisco switch must have DHCP snooping for all user VLANs to validate DHCP messages from untrusted sources.	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-101131	Medium	The Cisco 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-101137	Medium	The Cisco switch must have Dynamic Address Resolution Protocol (ARP) Inspection (DAI) enabled on all user VLANs.	DAI intercepts 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 the packet to the appropriate...
V-101135	Medium	The Cisco 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-101149	Medium	The Cisco switch must have all disabled switch ports assigned to an unused VLAN.	A disabled port that is assigned to a user or management VLAN may become enabled by accident or by an attacker and as a result may gain access to that VLAN as a member.
V-101143	Medium	The Cisco switch must implement Rapid Spanning Tree Protocol (STP) where VLANs span multiple switches with redundant links.	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 provide high...
V-101147	Medium	The Cisco 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-101145	Medium	The Cisco 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-101129	Medium	The Cisco switch must have Spanning Tree Protocol (STP) Loop Guard enabled.	The 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 transitions to the forwarding...
V-101121	Medium	The Cisco switch must be configured for authorized users to remotely view, in real time, all content related to an established user session from a component separate from the Cisco 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-101123	Medium	The Cisco switch must authenticate all 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-101127	Medium	The Cisco switch must have Bridge Protocol Data Unit (BPDU) Guard enabled on all user-facing or untrusted access switch ports.	If a rogue switch is introduced into the topology and transmits a BPDU with a lower bridge priority than the existing root bridge, it will become the new root bridge and cause a topology change,...
V-101139	Low	The Cisco switch must have Storm Control configured on all host-facing switchports.	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-101141	Low	The Cisco switch must have IGMP or MLD Snooping configured on all VLANs.	IGMP and MLD snooping provide 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-101161	Low	The Cisco switch must not have any switchports 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-101125	Low	The Cisco 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....