V-265981

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 must be short, which will require frequent re-signing. To minimize the impact of a compromised ZSK, a zone administrator must set a signature validity period of one week for RRSIGs covering the DNSKEY RRSet in the zone (the RRSet that contains the ZSK and KSK for the zone). The DNSKEY RRSet can be re-signed without performing a ZSK rollover, but scheduled ZSK rollover must still be performed at regular intervals.

Check Content

KSK validity period:
From the BIG-IP GUI:
1. DNS.
2. Delivery.
3. Keys.
4. DNSSEC Key List.
5. Click the Name of the KSK.
6. Verify the "Signature Validity Period" is between two and seven days.

ZSK validity period:
From the BIG-IP GUI:
1. DNS.
2. Delivery.
3. Keys.
4. DNSSEC Key List.
5. Click the Name of the ZSK.
6. Verify the "Signature Validity Period" is between two and seven days.

If the BIG-IP appliance is not configured with a validity period for the RRSIGs covering a zones DNSKEY RRSet of no less than two days and no more than one week, this is a finding.