T1599.001sub-technique of T1599 Network Boundary Bridging

Network Address Translation Traversal

Network Devicesnothing on this site yetT1599.001 on attack.mitre.org

Adversaries may bridge network boundaries by modifying a network device’s Network Address Translation (NAT) configuration. Malicious modifications to NAT may enable an adversary to bypass restrictions on traffic routing that otherwise separate trusted and untrusted networks. Network devices such as routers and firewalls that connect multiple networks together may implement NAT during the process of passing packets between networks.

MITRE ATT&CK 19.2, retrieved 2026-09-12

If this is happening now

1

Checklists and playbooks to open while the alert is still live.

how MITRE says to see it

Detection Strategy for Network Address Translation Traversal

  • Defenders may observe unauthorized or anomalous changes to NAT configurations, including the addition of new translation rules or modifications to existing ones. Suspicious behaviors include sudden introduction of NAT mappings bridging segmented networks, new port address translation rules that obscure true source...

what reduces it

  • M1037 Filter Network Traffic. Block Traffic Upon identifying a compromised network device being used to bridge a network boundary, block the malicious packets using an unaffected network device in path, such as a firewall or a router that has not been compromised. Continue to monitor for additional activity and to ensure that the blocks are indeed effective.
  • M1043 Credential Access Protection. Some embedded network devices are capable of storing passwords for local accounts in either plain-text or encrypted formats. Ensure that, where available, local passwords are always encrypted, per vendor recommendations.
  • M1027 Password Policies. Refer to NIST guidelines when creating password policies.
  • M1026 Privileged Account Management. Restrict administrator accounts to as few individuals as possible, following least privilege principles. Prevent credential overlap across systems of administrator and privileged accounts, particularly between network and non-network platforms, such as servers or endpoints.
  • M1032 Multi-factor Authentication. Use multi-factor authentication for user and privileged accounts. Most embedded network devices support TACACS+ and/or RADIUS. Follow vendor prescribed best practices for hardening access control.

The description, detection analytics and mitigations are reproduced from MITRE ATT&CK, version 19.2, under its terms of use. The checklists, hunts, labs and everything else linked here are this site’s.