TOSS must prevent IPv4 Internet Control Message Protocol (ICMP) redirect messages from being accepted.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-253130 | TOSS-04-040890 | SV-253130r991589_rule | CCI-000366 | medium |
| 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. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide | 2025-05-08 | |||
Details
Check Text (C-253130r991589_chk)
Verify TOSS will not accept IPv4 ICMP redirect messages.
Note: If IPv4 is disabled on the system, this requirement is Not Applicable.
Check the value of the default "accept_redirects" variables with the following command:
$ sudo 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", a line is not returned, or the line is commented out, this is a finding.
Fix Text (F-56533r825061_fix)
Configure TOSS to prevent IPv4 ICMP redirect messages from being accepted 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 the appropriate file under "/etc/sysctl.d":
net.ipv4.conf.default.accept_redirects=0