Title

TOSS must not accept router advertisements on all IPv6 interfaces. (Cat II impact)

Discussion

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. An illicit router advertisement message could result in a man-in-the-middle attack.

Check Content

Verify TOSS does not accept router advertisements on all IPv6 interfaces, unless the system is a router. Note: If IPv6 is disabled on the system, this requirement is Not Applicable. Check to see if router advertisements are not accepted by using the following command: $ sudo sysctl net.ipv6.conf.all.accept_ra net.ipv6.conf.all.accept_ra = 0 If the "accept_ra" value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Fix Text

Configure TOSS to not accept router advertisements on all IPv6 interfaces unless the system is a router with the following commands: $ sudo sysctl -w net.ipv6.conf.all.accept_ra=0 If "0" is not the system's default value then add or update the following lines in the appropriate file under "/etc/sysctl.d": net.ipv6.conf.all.accept_ra=0

Additional Identifiers

Rule ID: SV-253121r991589_rule

Vulnerability ID: V-253121

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

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