Detections
Analytics
OL09-00-006020 - OL 9 must ignore Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages.
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.This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.
Solution
Configure OL 9 to ignore IPv4 ICMP redirect messages.Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory:
net.ipv4.conf.all.accept_redirects = 0
Load settings from all system configuration files with the following command:
$ sudo sysctl --system
See Also
https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Oracle_Linux_9_V1R5_STIG.zip
Item Details
Audit Name: DISA Oracle Linux 9 STIG v1r5
Category: CONFIGURATION MANAGEMENT
References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-271864r1092304_rule, STIG-ID|OL09-00-006020, Vuln-ID|V-271864
Plugin: Unix
Control ID: a31886bd02a7987767edc98f7d041df28969a84dc53d0003fb8a0cb301a47a39