Cisco IOS XE Switch RTR Security Technical Implementation Guide
Rules, Groups, and Values defined within the XCCDF Benchmark
-
The Cisco perimeter switch must be configured to restrict it from accepting outbound IP packets that contain an illegitimate address in the source address field via egress filter or by enabling Unicast Reverse Path Forwarding (uRPF).
A compromised host in an enclave can be used by a malicious platform to launch cyberattacks on third parties. This is a common practice in "botnets", which are a collection of compromised computers...Rule High Severity -
The Cisco perimeter switch must be configured to filter ingress traffic at the external interface on an inbound direction.
Access lists are used to separate data traffic into that which it will route (permitted packets) and that which it will not route (denied packets). Secure configuration of switches makes use of acc...Rule Medium Severity -
The Cisco perimeter switch must be configured to have Proxy ARP disabled on all external interfaces.
When Proxy ARP is enabled on a switch, it allows that switch to extend the network (at Layer 2) across multiple interfaces (LAN segments). Because proxy ARP allows hosts from different LAN segments...Rule Medium Severity -
The Cisco switch must be configured to only permit management traffic that ingresses and egresses the out-of-band management (OOBM) interface.
The OOBM access switch will connect to the management interface of the managed network elements. The management interface can be a true OOBM interface or a standard interface functioning as the man...Rule Medium Severity -
The Cisco BGP switch must be configured to reject inbound route advertisements from a customer edge (CE) switch for prefixes that are not allocated to that customer.
As a best practice, a service provider should only accept customer prefixes that have been assigned to that customer and any peering autonomous systems. A multi-homed customer with BGP speaking swi...Rule Medium Severity -
The Cisco BGP switch must be configured to reject outbound route advertisements for any prefixes that do not belong to any customers or the local autonomous system (AS).
Advertisement of routes by an autonomous system for networks that do not belong to any of its customers pulls traffic away from the authorized network. This causes a denial of service (DoS) on the ...Rule Medium Severity -
The Cisco BGP switch must be configured to use the maximum prefixes feature to protect against route table flooding and prefix de-aggregation attacks.
The effects of prefix de-aggregation can degrade switch performance due to the size of routing tables and also result in black-holing legitimate traffic. Initiated by an attacker or a misconfigured...Rule Medium Severity -
The Cisco BGP switch must be configured to use its loopback address as the source address for iBGP peering sessions.
Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the BGP switches. It is easier to construct appropriate ingress filter...Rule Low Severity -
The Cisco MPLS switch must be configured to synchronize Interior Gateway Protocol (IGP) and LDP to minimize packet loss when an IGP adjacency is established prior to LDP peers completing label exchange.
Packet loss can occur when an IGP adjacency is established and the switch begins forwarding packets using the new adjacency before the LDP label exchange completes between the peers on that link. P...Rule Low Severity -
The MPLS switch with RSVP-TE enabled must be configured with message pacing to adjust maximum burst and maximum number of RSVP messages to an output queue based on the link speed and input queue size of adjacent core switches.
RSVP-TE can be used to perform constraint-based routing when building LSP tunnels within the network core that will support QoS and traffic engineering requirements. RSVP-TE is also used to enable ...Rule Low Severity -
The Cisco PE switch must be configured to have each Virtual Routing and Forwarding (VRF) instance with the appropriate Route Target (RT).
The primary security model for an MPLS L3VPN as well as a VRF-lite infrastructure is traffic separation. Each interface can only be associated to one VRF, which is the fundamental framework for tra...Rule High Severity -
The Cisco PE switch must be configured to have each VRF with the appropriate Route Distinguisher (RD).
An RD provides uniqueness to the customer address spaces within the MPLS L3VPN infrastructure. The concept of the VPN-IPv4 and VPN-IPv6 address families consists of the RD prepended before the IP a...Rule Medium Severity -
The Cisco PE switch providing Virtual Private LAN Services (VPLS) must be configured to have all attachment circuits defined to the virtual forwarding instance (VFI) with the globally unique VPN ID assigned for each customer VLAN.
VPLS defines an architecture that delivers Ethernet multipoint services over an MPLS network. Customer Layer 2 frames are forwarded across the MPLS core via pseudowires using IEEE 802.1q Ethernet b...Rule High Severity -
The Cisco PE switch providing Virtual Private LAN Services (VPLS) must be configured to have traffic storm control thresholds on CE-facing interfaces.
A traffic storm occurs when packets flood a VPLS bridge, creating excessive traffic and degrading network performance. Traffic storm control prevents VPLS bridge disruption by suppressing traffic w...Rule Medium Severity -
The Cisco PE switch must be configured with Unicast Reverse Path Forwarding (uRPF) loose mode enabled on all CE-facing interfaces.
The uRPF feature is a defense against spoofing and denial-of-service (DoS) attacks by verifying if the source address of any ingress packet is reachable. To mitigate attacks that rely on forged sou...Rule Medium Severity -
The Cisco PE switch must be configured to ignore or drop all packets with any IP options.
Packets with IP options are not fast-switched and therefore must be punted to the switch processor. Hackers who initiate denial-of-service (DoS) attacks on switches commonly send large streams of p...Rule Medium Severity -
The Cisco PE switch must be configured to enforce a Quality-of-Service (QoS) policy to provide preferred treatment for mission-critical applications.
Different applications have unique requirements and toleration levels for delay, jitter, bandwidth, packet loss, and availability. To manage the multitude of applications and services, a network re...Rule Low Severity -
The Cisco P switch must be configured to enforce a Quality-of-Service (QoS) policy to provide preferred treatment for mission-critical applications.
Different applications have unique requirements and toleration levels for delay, jitter, bandwidth, packet loss, and availability. To manage the multitude of applications and services, a network re...Rule Low Severity -
The Cisco multicast switch must be configured to bind a Protocol Independent Multicast (PIM) neighbor filter to interfaces that have PIM enabled.
PIM is a routing protocol used to build multicast distribution trees for forwarding multicast traffic across the network infrastructure. PIM traffic must be limited to only known PIM neighbors by c...Rule Medium Severity -
The Cisco multicast Rendezvous Point (RP) switch must be configured to filter Protocol Independent Multicast (PIM) Register messages received from the Designated switch (DR) for any undesirable multicast groups and sources.
Real-time multicast traffic can entail multiple large flows of data. An attacker can flood a network segment with multicast packets, over-using the available bandwidth and thereby creating a denial...Rule Low Severity -
The Cisco multicast Rendezvous Point (RP) must be configured to rate limit the number of Protocol Independent Multicast (PIM) Register messages.
When a new source starts transmitting in a PIM Sparse Mode network, the DR will encapsulate the multicast packets into register messages and forward them to the RP using unicast. This process can b...Rule Medium Severity -
The Cisco multicast Designated switch (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join only multicast groups that have been approved by the organization.
Real-time multicast traffic can entail multiple large flows of data. Large unicast flows tend to be fairly isolated (i.e., someone doing a file download here or there), whereas multicast can have b...Rule Low Severity -
The Cisco multicast Designated switch (DR) must be configured to filter the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Report messages to allow hosts to join a multicast group only from sources that have been approved by the organization.
Real-time multicast traffic can entail multiple large flows of data. Large unicast flows tend to be fairly isolated (i.e., someone doing a file download here or there), whereas multicast can have b...Rule Medium Severity -
The Cisco multicast Designated switch (DR) must be configured to limit the number of mroute states resulting from Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Host Membership Reports.
The current multicast paradigm can let any host join any multicast group at any time by sending an IGMP or MLD membership report to the DR. In a Protocol Independent Multicast (PIM) Sparse Mode net...Rule Medium Severity -
The Cisco multicast Designated switch (DR) must be configured to set the shortest-path tree (SPT) threshold to infinity to minimalize source-group (S, G) state within the multicast topology where Any Source Multicast (ASM) is deployed.
ASM can have many sources for the same groups (many-to-many). For many receivers, the path via the RP may not be ideal compared with the shortest path from the source to the receiver. By default, t...Rule Medium Severity -
The Cisco Multicast Source Discovery Protocol (MSDP) switch must be configured to only accept MSDP packets from known MSDP peers.
MSDP peering with customer network switches presents additional risks to the DISN Core, whether from a rogue or misconfigured MSDP-enabled switch. To guard against an attack from malicious MSDP tra...Rule Medium Severity -
The Cisco Multicast Source Discovery Protocol (MSDP) switch must be configured to filter received source-active multicast advertisements for any undesirable multicast groups and sources.
The interoperability of BGP extensions for interdomain multicast routing and MSDP enables seamless connectivity of multicast domains between autonomous systems. MP-BGP advertises the unicast prefix...Rule Low Severity -
The Cisco Multicast Source Discovery Protocol (MSDP) switch must be configured to filter source-active multicast advertisements to external MSDP peers to avoid global visibility of local-only multicast sources and groups.
To avoid global visibility of local information, there are a number of source-group (S, G) states in a PIM-SM domain that must not be leaked to another domain, such as multicast sources with privat...Rule Low Severity -
The Cisco Multicast Source Discovery Protocol (MSDP) switch must be configured to use a loopback address as the source address when originating MSDP traffic.
Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of MSDP switches. It is easier to construct appropriate ingress filters f...Rule Low Severity -
The Cisco switch must be configured to have Cisco Express Forwarding enabled.
The Cisco Express Forwarding (CEF) switching mode replaces the traditional Cisco routing cache with a data structure that mirrors the entire system routing table. Because there is no need to build ...Rule Medium Severity -
The Cisco switch must be configured to advertise a hop limit of at least 32 in Switch Advertisement messages for IPv6 stateless auto-configuration deployments.
The Neighbor Discovery protocol allows a hop limit value to be advertised by routers in a Router Advertisement message being used by hosts instead of the standardized default value. If a very small...Rule Low Severity -
The Cisco switch must not be configured to use IPv6 Site Local Unicast addresses.
As currently defined, site local addresses are ambiguous and can be present in multiple sites. The address itself does not contain any indication of the site to which it belongs. The use of site-lo...Rule Medium Severity -
The Cisco perimeter switch must be configured to suppress Router Advertisements on all external IPv6-enabled interfaces.
Many of the known attacks in stateless autoconfiguration are defined in RFC 3756 were present in IPv4 ARP attacks. To mitigate these vulnerabilities, links that have no hosts connected such as the ...Rule Medium Severity -
The Cisco perimeter switch must be configured to drop IPv6 undetermined transport packets.
One of the fragmentation weaknesses known in IPv6 is the undetermined transport packet. This packet contains an undetermined protocol due to fragmentation. Depending on the length of the IPv6 exten...Rule Medium Severity -
The Cisco perimeter switch must be configured drop IPv6 packets with a Routing Header type 0, 1, or 3-255.
The routing header can be used maliciously to send a packet through a path where less robust security is in place, rather than through the presumably preferred path of routing protocols. Use of the...Rule Medium Severity -
The Cisco perimeter switch must be configured to drop IPv6 packets containing a Destination Option header with invalid option type values.
These options are intended to be for the Hop-by-Hop header only. The optional and extensible natures of the IPv6 extension headers require higher scrutiny since many implementations do not always d...Rule Medium Severity -
The Cisco perimeter switch must be configured to drop IPv6 packets containing a Hop-by-Hop or Destination Option extension header with an undefined option type.
The optional and extensible natures of the IPv6 extension headers require higher scrutiny since many implementations do not always drop packets with headers that it cannot recognize, and hence coul...Rule Medium Severity -
SRG-NET-000018-RTR-000001
Group -
The Cisco switch must be configured to have Internet Control Message Protocol (ICMP) redirect messages disabled on all external interfaces.
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Switches automatically send ICMP messages under a wide variety of conditions. Redirect ICMP message...Rule Medium Severity -
SRG-NET-000078-RTR-000001
Group -
SRG-NET-000076-RTR-000001
Group -
SRG-NET-000168-RTR-000078
Group -
The Cisco switch must be configured to enable routing protocol authentication using FIPS 198-1 algorithms with keys not exceeding 180 days of lifetime.
A rogue router could send a fictitious routing update to convince a site's perimeter router to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to l...Rule Medium Severity -
SRG-NET-000019-RTR-000007
Group -
SRG-NET-000362-RTR-000109
Group -
The Cisco switch must not be configured to have any zero-touch deployment feature enabled when connected to an operational network.
Network devices that are configured via a zero-touch deployment or auto-loading feature can have their startup configuration or image pushed to the device for installation via TFTP or Remote Copy (...Rule Medium Severity -
SRG-NET-000362-RTR-000110
Group -
SRG-NET-000362-RTR-000111
Group -
The Cisco switch must be configured to have Gratuitous ARP disabled on all external interfaces.
A gratuitous ARP is an ARP broadcast in which the source and destination MAC addresses are the same. It is used to inform the network about a host IP address. A spoofed gratuitous ARP message can c...Rule Medium Severity -
SRG-NET-000362-RTR-000112
Group
Node 2
The content of the drawer really is up to you. It could have form fields, definition lists, text lists, labels, charts, progress bars, etc. Spacing recommendation is 24px margins. You can put tabs in here, and can also make the drawer scrollable.