3.4.1.2 Ensure IPv4 loopback traffic is configured

Information

Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network (127.0.0.0/8).

Rationale:

Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network (127.0.0.0/8) traffic should be seen, all other interfaces should ignore traffic on this network as an anti-spoofing measure.

Solution

Run the following commands to implement the loopback rules:

# iptables -A INPUT -i lo -j ACCEPT

# iptables -A OUTPUT -o lo -j ACCEPT

# iptables -A INPUT -s 127.0.0.0/8 -j DROP

See Also

https://workbench.cisecurity.org/benchmarks/6709

Item Details

Category: SECURITY ASSESSMENT AND AUTHORIZATION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CA-9, 800-53|SC-7, 800-53|SC-7(5), CSCv7|9.4

Plugin: Unix

Control ID: 420bcb5d6d51c19238ed8c63e9d8d5db34c3ce19e445017a3179a45225029c31