Title

On the BIND 9.x server the private key corresponding to the ZSK, stored on name servers accepting dynamic updates, must be owned by root. (Cat II impact)

Discussion

The private ZSK key must be protected from unauthorized access. This strategy is not feasible in situations in which the DNSSEC-aware name server has to support dynamic updates. To support dynamic update transactions, the DNSSEC-aware name server (which usually is a primary authoritative name server) has to have both the zone file master copy and the private key corresponding to the zone-signing key (ZSK-private) online to immediately update the signatures for the updated RRsets.

Check Content

If the server is in a classified network, this is Not Applicable. Note: This check only verifies for ZSK key file ownership. Permissions for key files are required under V-72451, BIND-9X-001132 and V-72461, BIND-9X-001142. For each signed zone file, identify the ZSK "key id" number: # cat <signed_zone_file> | grep -i "zsk" ZSK; alg = ECDSAP256SHA256; key id = 22335 Using the ZSK "key id", identify the private ZSK. Kexample.com.+008+22335.private Verify that the private ZSK is owned by root: # ls -l <ZSK_key_file> -r------- 1 root root 1776 Jul 3 17:56 Kexample.com.+008+22335.private If the key file is not owned by root, this is a finding.

Fix Text

Change the ownership of the ZSK private key to the root account. # chown root <key_file>

Additional Identifiers

Rule ID: SV-207589r879887_rule

Vulnerability ID: V-207589

Group Title: SRG-APP-000516-DNS-000111

Expert Comments

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