3.1.9 Require instance name for discovery requests

Information

The discover parameter determines what kind of discovery requests, if any, the DB2 server will fulfill. It is recommended that the DB2 server only fulfill requests from clients that know the given instance name (discover parameter value of known).

Discovery capabilities may be used by a malicious entity to derive the names of and target DB2 instances. In this configuration, the client has to specify a known instance name to be able to detect the instance.

Solution

The recommended value is KNOWN. Note: this requires a DB2 restart.
1. Attach to the DB2 instance.
db2 => attach to $DB2INSTANCE
2. Run the following command from the DB2 command window:
db2 => update database manager configuration using discover known
3. Restart the DB2 instance.
db2 => db2stop
db2 => db2start
Impact:
The implementation of this recommendation results in a brief downtime. It is advisable to ensure that the setting is implemented during an approved maintenance window.
Default Value:
The default value for discover is SEARCH.

See Also

https://workbench.cisecurity.org/files/1654