Title

DNS software does not run on dedicated (running only those services required for DNS) hardware. The only currently accepted exception of this requirement is Windows 2000/2003 DNS, which must run on a domain controller that is integrated with Active Directory services. (Cat II impact)

Discussion

Even a securely configured operating system is vulnerable to the flaws of the programs that run on it. To prevent DNS software from being subjected to the vulnerabilities of other programs and services, the DNS server will not run other programs and services at all, or at least run only those programs that are necessary for either OS or DNS support.

Check Content

During the initial interviews, the reviewer may have already identified that a name server is supporting production services other than DNS. At this point, the reviewer should validate that response through a hands-on check of the actual name server. UNIX The only permitted services to be running on a DNS UNIX BIND server are those implementing: - DNS - Secure shell - Host intrusion detection - Host file integrity - Network management or monitoring - Anti-virus - Backup - UPS - NTP The below are not permitted: Services started through inetd.conf: admind, chargen, echo, etherstatd, fingerd, ftpd, httpd, ICQ server, identd, netstat, netstatd, nit, nntp, nsed, nsemntd, pfilt, portd, quaked, rexd, rexecd, rje_mapper, rlogind, rpc_3270, rpc_alias, rpc_database, rpc_keyserv, rpc_sched, rquotad, rsh, rstatd, rusersd, selectd, serverd, showfhd, sprayd, statmon, sunlink_mapper, sysstat, talkd, telnetd, tfsd, tftpd, timed, ttdb, ugidd, uucpd, and walld. Services started at boot time: NFS client, NFS server process and SNMP daemon, automounter, printer queue daemon, and RPC portmapper. (For Solaris, disable the following scripts in rc2.d: S73nfs.client, S74autofs, S80lp, S71rpc, and S99dtlogin and the following scripts in rc3.d: S15nfs.server and S76snmpd.) Instruction: In the presence of the reviewer, the SA should enter the following command: ps –ef Based on the command output, the reviewer should be able to determine if the machine is dedicated to DNS or if it is supporting other production services. If additional services are running and it is determined the name server is not running on dedicated hardware, then this is a finding.

Fix Text

Working with DNS and Systems Administrators, the IAO should migrate the DNS software to dedicated hardware for the purpose of supporting the name server or remove/migrate any additional programs or applications, running on the name server to ensure the name server is running on dedicated hardware.

Additional Identifiers

Rule ID: SV-4473r3_rule

Vulnerability ID: V-4473

Group Title:

Expert Comments

CCIs tied to check.

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