SLES-15-040340 - The SUSE operating system must not allow interfaces to accept Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages by default.

Information

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 SUSE operating system to not accept IPv4 ICMP redirect messages by default by running the following command as an administrator:

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

If '0' is not the system's default value, add or update the following line in '/etc/sysctl.d/99-stig.conf':

> sudo sh -c 'echo 'net.ipv4.conf.default.accept_redirects=0' >> /etc/sysctl.d/99-stig.conf'

> sudo sysctl --system

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_SLES_15_V2R2_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-235019r991589_rule, STIG-ID|SLES-15-040340, Vuln-ID|V-235019

Plugin: Unix

Control ID: bb63dc107b3d4e4b99edfcc9f0a08d150a7e3147cc3e54b66feff731da2b3166