The SUSE operating system must not allow interfaces to accept Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages by default.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-217292 | SRG-OS-000480-GPOS-00227 | SLES-12-030400 | SV-217292r991589_rule | 2024-11-25 | 3 |
| Description |
|---|
| 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. |
| ℹ️ Check |
|---|
| Verify the SUSE operating system ignores IPv4 ICMP redirect messages. Check the value of the "accept_redirects" variables with the following command: # sysctl net.ipv4.conf.default.accept_redirects net.ipv4.conf.default.accept_redirects = 0 If the returned line does not have a value of "0" this is a finding. |
| ✔️ Fix |
|---|
| Configure the SUSE operating system ignores IPv4 ICMP redirect messages by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value): net.ipv4.conf.default.accept_redirects = 0 Run the following command to apply this value: # sysctl --system |