Title

A BIND 9.x server implementation must maintain the integrity and confidentiality of DNS information while it is being prepared for transmission, in transmission, and in use and t must perform integrity verification and data origin verification for all DNS information. (Cat I impact)

Discussion

DNSSEC is required for securing the DNS query/response transaction by providing data origin authentication and data integrity verification through signature verification and the chain of trust Failure to accomplish data origin authentication and data integrity verification could have significant effects on DNS Infrastructure. The resultant response could be forged, it may have come from a poisoned cache, the packets could have been intercepted without the resolver's knowledge, or resource records could have been removed that would result in query failure or denial of service Failure to validate name server replies would cause many networking functions and communications to be adversely affected. With DNS, the presence of Delegation Signer (DS) records associated with child zones informs clients of the security status of child zones. These records are crucial to the DNSSEC chain of trust model. Each parent domain's DS record is used to verify the DNSKEY record in its subdomain, from the top of the DNS hierarchy down. Failure to validate the chain of trust used with DNSSEC would have a significant impact on the security posture of the DNS server. Non-validated trust chains may contain rouge DNS servers and allow those unauthorized servers to introduce invalid data into an organizations DNS infrastructure. A compromise of this type would be difficult to detect and may have devastating effects on the validity and integrity of DNS zone information. Satisfies: SRG-APP-000213-DNS-000024, SRG-APP-000215-DNS-000026, SRG-APP-000219-DNS-000028, SRG-APP-000219-DNS-000029, SRG-APP-000219-DNS-000030, SRG-APP-000347-DNS-000041, SRG-APP-000348-DNS-000042, SRG-APP-000349-DNS-000043, SRG-APP-000420-DNS-000053, SRG-APP-000421-DNS-000054, SRG-APP-000422-DNS-000055, SRG-APP-000423-DNS-000056, SRG-APP-000424-DNS-000057, SRG-APP-000425-DNS-000058, SRG-APP-000426-DNS-000059, SRG-APP-000441-DNS-000066, SRG-APP-000442-DNS-000067, SRG-APP-000516-DNS-000089

Check Content

If the server is in a classified network, this is Not Applicable. If the server is forwarding all queries to the ERS, this is Not Applicable as the ERS validates. Verify that DNSSEC is enabled. Inspect the "named.conf" file for the following: dnssec-enable yes; If "dnssec-enable" does not exist or is not set to "yes", this is a finding. Verify that each zone on the name server has been signed. Identify each zone file that the name sever is responsible for and search each file for the "DNSKEY" entries: # less <signed_zone_file> 86400 DNSKEY 257 3 8 ( HASHED_KEY ) ; KSK; alg = ECDSAP256SHA256; key id = 31225 86400 DNSKEY 256 3 8 ( HASHED_KEY ) ; ZSK; alg = ECDSAP256SHA256; key id = 52179 Ensure that there are separate "DNSKEY" entries for the "KSK" and the "ZSK" If the "DNSKEY" entries are missing, the zone file is not signed. If the zone files are not signed, this is a finding.

Fix Text

Set the "dnssec-enable" option to yes. Sign each zone file that the name server is responsible for. Configure each zone the name server is responsible for to use a DNSSEC signed zone.

Additional Identifiers

Rule ID: SV-207577r879633_rule

Vulnerability ID: V-207577

Group Title: SRG-APP-000213-DNS-000024

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.