Enable DNS Security

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Configure DNS signature policy settings to send malware DNS queries to the defined sinkhole.
Select
Objects
Security Profiles
Anti-Spyware
.
Create or modify an existing profile, or select one of the existing default profiles and clone it.
Name
the profile and, optionally, provide a description.
Select the
DNS Signatures
>
Policies & Settings
tab.
If the
Palo Alto Networks
DNS Security
source is not present, click
Add
and select it from the list.
Select an action to be taken when DNS lookups are made to known malware sites for the DNS Security signature source. The options are alert, allow, block, or sinkhole. Verify that the action is set to sinkhole.
(
Optional
) In the
Packet Capture
drop-down, select
single-packet
to capture the first packet of the session or
extended-capture
to set between 1-50 packets. You can then use the packet captures for further analysis.
In the
DNS Sinkhole Settings
section, verify that
Sinkhole
is enabled. For your convenience, the default Sinkhole address (sinkhole.paloaltonetworks.com) is set to access a Palo Alto Networks server. Palo Alto Networks can automatically refresh this address through content updates.
If you want to modify the
Sinkhole IPv4
or
Sinkhole IPv6
address to a local server on your network or to a loopback address, see Configure the Sinkhole IP Address to a Local Server on Your Network.
Click
OK
to save the Anti-Spyware profile.

Attach the Anti-Spyware profile to a Security policy rule.
Select
Policies
Security
.
Select or create a
Security Policy Rule
.
On the
Actions
tab, select the
Log at Session End
check box to enable logging.
In the Profile Setting section, click the
Profile Type
drop-down to view all
Profiles
. From the
Anti-Spyware
drop-down and select the new or modified profile.
Click
OK
to save the policy rule.
Test that the policy action is enforced.
Access the following test domains to verify that the policy action for a given threat type is being enforced:
Malware— test-malware.testpanw.com
C2— test-c2.testpanw.com
DGA— test-dga.testpanw.com
DNS Tunneling— test-dnstun.testpanw.com
To monitor the activity on the firewall:
Select
ACC
and add a URL Domain as a global filter to view the Threat Activity and Blocked Activity for the domain you accessed.
Monitor
Logs
Threat
Select and filter by
(action eq sinkhole)
to view logs on sinkholed domains.
Identify Infected Traffic Hosts in the Traffic Logs
(Optional) Add domain signature exceptions in cases where false-positives occur.
Select

Objects

Security Profiles

Anti-Spyware

.

Select a profile to modify.

Add

or modify the Anti-Spyware profile from which you want to exclude the threat signature, and select

DNS Signatures > Exceptions

.

Search for a DNS signature to exclude by entering the name or FQDN.

Select the

DNS Threat ID

for the DNS signature that you want to exclude from enforcement.

Click

OK

to save your new or modified Anti-Spyware profile.


(Optional) Configure the DNS signature lookup timeout setting. If the firewall is unable to retrieve a signature verdict in the allotted time due to connectivity issues, the request, including all subsequent DNS responses, are passed through. You can check the average latency to verify that the requests fall within the configured period. If the average latency exceeds the configured period, consider updating the setting to a value that is higher than the average latency to prevent requests from timing out.
In the CLI, issue the following command to view the average latency.
show dns-proxy dns-signature
counters
The default timeout is 100 milliseconds.
Scroll down through the output to the latency section under the Signature query API heading and verify that the average latency falls within the defined timeout period. This latency indicates the amount of time it takes, on average, to retrieve a signature verdict from the DNS security service. Additional latency statistics for various latency periods can be found below the averages.
Signature query API:
	 .
		.
		.
	    [latency   ] :
        max    1870 (ms)  min    16(ms)  avg    27(ms)
          50 or less : 47246
          100 or less : 113
          200 or less : 25
          400 or less : 15
                 else : 21
If the average latency is consistency above the default timeout value, you can raise the setting so that the requests fall within a given period. Select
Device > Content-ID
and update the
Realtime Signature Lookup
setting.
Commit the changes.