IPSEC NAT Traversal Port Activityedit

Detects events that could be describing IPSEC NAT Traversal traffic. IPSEC is a VPN technology that allows one system to talk to another using encrypted tunnels. NAT Traversal enables these tunnels to communicate over the Internet where one of the sides is behind a NAT router gateway. This may be common on your network, but this technique is also used by threat actors to avoid detection.

Rule type: query

Rule indices:

  • filebeat-*

Severity: low

Risk score: 21

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum signals per execution: 100


  • Elastic
  • Network

Version: 2 (version history)

Added (Elastic Stack release): 7.6.0

Last modified (Elastic Stack release): 7.6.1

Potential false positivesedit

Some networks may utilize these protocols but usage that is unfamiliar to local network administrators can be unexpected and suspicious. Because this port is in the ephemeral range, this rule may false under certain conditions, such as when an application server with a public IP address replies to a client which has used a UDP port in the range by coincidence. This is uncommon but such servers can be excluded.

Rule queryedit

network.transport:udp and destination.port:4500

Threat mappingedit


Rule version historyedit

Version 2 (7.6.1 release)
  • Removed auditbeat-*, packetbeat-*, and winlogbeat-* from the rule indices.