The BIND 9.x server implementation must utilize separate TSIG key-pairs when securing server-to-server transactions.

Server-to-server (zone transfer) transactions are provided by TSIG, which enforces mutual server authentication using a key that is unique to each server pair (TSIG), thus uniquely identifying the other server.

Enforcing separate TSIG key-pairs provides another layer of protection for the BIND implementation in the event that a TSIG key is compromised. This additional layer of security provides the DNS administrators with the ability to change a compromised TSIG key with a minimal disruption to DNS operations.

Failure to identify devices and authenticate devices can lead to malicious activity, such as a Man-In-The-Middle attack where an attacker could pose as an authorized name server, and redirect legitimate customers to malicious websites. A failure on this part could also lead to a Denial of Service of any and all DNS services provided to an organizations network infrastructure.

Verify that the BIND 9.x server is configured to utilize separate TSIG key-pairs when securing server-to-server transactions. Inspect the "named.conf" file for the presence of TSIG key statements:

On the master name server, this is an example of a configured key statement:

key tsig_example. { algorithm hmac-SHA1; include "tsig-example.key"; };

zone "disa.mil" { type master; file "db.disa.mil"; allow-transfer { key tsig_example.; }; };

On the slave name server, this is an example of a configured key statement:

key tsig_example. { algorithm hmac-SHA1; include "tsig-example.key"; };

server <ip_address> { keys { tsig_example }; };

zone "disa.mil" { type slave; masters { <ip_address>; }; file "db.disa.mil"; };

Verify that each TSIG key-pair listed is only used by a single key statement: # cat <tsig_key_file>

If any TSIG key-pair is being used by more than one key statement, this is a finding.

Create a separate TSIG key-pair for each key statement listed in the named.conf file.

Configure the name server to utilize separate TSIG key-pairs for each key statement listed in the named.conf file.

Restart the BIND 9.x process.