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

Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. This applies to server-to-server (zone transfer) transactions only and is provided by TSIG/SIG(0), which enforces mutual server authentication using a key that is unique to each server pair (TSIG) or using PKI-based authentication (SIG[0]), thus uniquely identifying the other server.

Verify that the BIND 9.x server is configured to use separate TSIG key-pairs when securing server-to-server transactions.

Inspect the "named.conf" file for the presence of TSIG key statements:

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

key tsig_example. { algorithm hmac-SHA256; include "tsig-example.key"; };

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

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

key tsig_example. { algorithm hmac-SHA256; include "tsig-example.key"; };

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

zone "disa.mil" { type Secondary; Primarys { <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 use separate TSIG key-pairs for each key statement listed in the named.conf file.

Restart the BIND 9.x process.