UBTU-16-030560 - The Ubuntu operating system must prevent Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages from being accepted.

Information

Internet Control Message Protocol (ICMP) redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.

Solution

Configure the Ubuntu operating system to prevent Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages from being acceptedr with the following command:

# sudo sysctl -w net.ipv4.conf.default.accept_redirects=0

If '0' is not the system's default value then add or update the following line in '/etc/sysctl.conf' or in the appropriate file under '/etc/sysctl.d':

net.ipv4.conf.default.accept_redirects=0

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CAN_Ubuntu_16-04_LTS_V2R3_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-215149r610931_rule, STIG-ID|UBTU-16-030560, STIG-Legacy|SV-90559, STIG-Legacy|V-75879, Vuln-ID|V-215149

Plugin: Unix

Control ID: 75a8450a28e12893e841c6ca0255b3edc19b221e2bdd7596a6410f07e7e27d28