Information
The recommendation is to block chat via talk or ntalk. These services enable users to chat within terminal sessions.
Rationale:
These services use unsecured TCP and UDP protocols and can be snooped via the network.
Solution
Disable talk and write.
rmitab writesrv
chmod a-rwx /usr/sbin/writesrv
trustchk -u /usr/sbin/writesrv mode
Default Value:
ntalk is enabled