Destination NAT published with a broad service
At a glance
Base severity
Area
Platform
Evidence level
Benchmark reference
Reads the export, not the device
ConfigProof reads a configuration export. This control is evaluated against the objects in that file, and it reports what the file says. It does not connect to the device and sees no traffic, so a finding here describes the configuration, not what the firewall is doing right now.
Why it matters
The destination NAT rule matches service any, so traffic to every port of the published address matches the translation. Unless the rule also translates to one fixed port, each port is forwarded to the same port on the internal host, and which of that traffic reaches the host is left to the security rules.
How to fix it
Web interface
The steps below are written for the web interface. A finding raised on your own export carries the same steps with your object names filled in.
- Set the NAT rule service to the specific service object being published.
- Add the translated port so only that port is forwarded.
Command line
PAN-OS CLI, standalone firewall, vsys1
set vsys vsys1 rulebase nat rules <object-name> service <published-service>An example. Values in angle brackets are yours to supply; a finding on your own export fills in the names it read. Nothing here commits. Review the candidate configuration, then commit it yourself.
Read it back
show vsys vsys1 rulebase nat rules <object-name>Values to fill in2
- <object-name>
- The object's name, as it appears on your firewall
- <published-service>
- The service the application actually uses
Before you type it1
- A NAT rule matches the address before translation and a security rule matches the zone after it.
How to confirm the fix
- Confirm the published application uses only the ports you narrow the rule to.
Limits
- Multi-port applications sometimes need a broad NAT with a tight security rule in front. The paired security rule is listed in the finding.
Compliance references
No benchmark recommendation is mapped to this control in this version.
See it on your own firewall
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