STIGQter: STIG Summary: Arista MLS DCS-7000 Series RTR Security Technical Implementation Guide Version: 1 Release: 3 Benchmark Date: 24 Jul 2020:

The Arista Multilayer Switch must ensure all Exterior Border Gateway Protocol (eBGP) routers are configured to use Generalized TTL Security Mechanism (GTSM) or are configured to meet RFC3682.

DISA Rule

SV-75379r1_rule

Vulnerability Number

V-60921

Group Title

SRG-NET-000191-RTR-000081

Rule Version

AMLS-L3-000260

Severity

CAT II

CCI(s)

• CCI-002385 - The information system protects against or limits the effects of organization-defined types of denial of service attacks by employing organization-defined security safeguards.

Weight

10

Fix Recommendation

Configure all Exterior Border Gateway Protocol peering sessions to use Generalized TTL Security Mechanism (GTSM) or an equivalent configuration as per RFC3682.

For adjacent EBGP neighbors, under the router configuration section, enter:

config
router bgp [AS number]
neighbor [address] ebgp-multihop 255
exit
ip access-list [name]
permit tcp [src address/mask] [dst address/mask] eq bgp ttl eq 255 log
exit
control-plane
ip access-group [name] [direction]

Check Contents

Review the router configuration.

If it is not configured to use Generalized TTL Security Mechanism (GTSM) or is not configured to provide equivalent functionality as per RFC3682 for all Exterior Border Gateway Protocol peering sessions, this is a finding.

The Arista MLS does not have a command to enable GTSM. Instead, any EBGP neighbor statement must include the "ebgp-multihop [hop]" configuration statement, viewable in the "router bgp [AS number]" section of the running config. For adjacent peers, this number must be 255.

Additionally, the control-plane ACL must have a statement that matches against the neighbor's correct TTL to allow inbound packets to the Switch. The neighbor TTL must be 255 for an adjacent peer or the result of 255-(number of hops) for a multihop peer.

Vulnerability Number

V-60921

Documentable

False

Rule Version

AMLS-L3-000260

Severity Override Guidance

Review the router configuration.

If it is not configured to use Generalized TTL Security Mechanism (GTSM) or is not configured to provide equivalent functionality as per RFC3682 for all Exterior Border Gateway Protocol peering sessions, this is a finding.

The Arista MLS does not have a command to enable GTSM. Instead, any EBGP neighbor statement must include the "ebgp-multihop [hop]" configuration statement, viewable in the "router bgp [AS number]" section of the running config. For adjacent peers, this number must be 255.

Additionally, the control-plane ACL must have a statement that matches against the neighbor's correct TTL to allow inbound packets to the Switch. The neighbor TTL must be 255 for an adjacent peer or the result of 255-(number of hops) for a multihop peer.

Check Content Reference

M

Target Key

2823

Comments