V-285246

Discussion

The best way for a zone administrator to minimize the impact of a key compromise is by limiting the validity period of RRSIGs in the zone and in the parent zone. This strategy limits the time during which an attacker can take advantage of a compromised key to forge responses. An attacker that has compromised a ZSK can use that key only during the KSK's signature validity interval. An attacker that has compromised a KSK can use that key for only as long as the signature interval of the RRSIG covering the DS RR in the delegating parent. These validity periods should be short, which will require frequent re-signing. To prevent the impact of a compromised KSK, a delegating parent should set the signature validity period for RRSIGs covering DS RRs in the range of a few days to one week. This re-signing does not require frequent rollover of the parent's ZSK, but scheduled ZSK rollover should still be performed at regular intervals. Satisfies: SRG-APP-000214-DNS-000079, SRG-APP-000516-DNS-000078

Check Content

Verify that Infoblox RRSIGs covering the DS RR for a zone's delegated children are configured with a validity period no less than two days and no more than one week.

1. Navigate to the Data Management >> DNS tab. 
2. Click "Grid DNS Properties" (Toolbar menu).
3. Toggle "Advanced Mode", click the "DNSSEC" tab, and review the "Signature Validity" setting. 
4. Validate the Signature Validity is configured for a range of no less than two days and no more than one week. 
5. When complete, click "Cancel" to exit the "Properties" screen. 

If the "Signature Validity" period is less than two days or greater than one week, this is a finding.