TCP intercept features must be provided by the network device by implementing a filter to rate limit and protect publicly accessible servers from any TCP SYN flood attacks from an outside network.

From Perimeter Router Security Technical Implementation Guide Juniper

Part of Routers are not set to intercept TCP SYN attacks

SV-16144r3_rule TCP intercept features must be provided by the network device by implementing a filter to rate limit and protect publicly accessible servers from any TCP SYN flood attacks from an outside network.

Vulnerability discussion

The TCP SYN attack involves transmitting a volume of connections that cannot be completed at the destination. This attack causes the connection queues to fill up, thereby denying service to legitimate TCP users.

Check content

Review the device configuration to determine if TCP Intercept has been configured to mitigate TCP SYN Flood attacks. If TCP Intercept has not been implemented, this is a finding. CAVEAT: If the site has implemented SYN flood protection for the network using the perimeter firewall or IPS (or an IDS if it is configured to dynamically configure upstream router to block the attack), there is not an additional requirement to implement it on the router.

Fix text

Configure the device to use TCP Intercept to protect against TCP SYN attacks from outside the network.

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