RHEL 9 network interfaces must not be in promiscuous mode.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257941	RHEL-09-251040	SV-257941r991589_rule		Medium

Description

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems. If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the information systems security officer (ISSO) and restricted to only authorized personnel.

STIG	Date
Red Hat Enterprise Linux 9 Security Technical Implementation Guide	2024-12-04

Details

Check Text (C-61682r925808_chk)

Verify network interfaces are not in promiscuous mode with the following command:

$ ip link | grep -i promisc

If network interfaces are found on the system in promiscuous mode and their use has not been approved by the ISSO and documented, this is a finding.

Fix Text (F-61606r925809_fix)

Configure network interfaces to turn off promiscuous mode unless approved by the ISSO and documented.

Set the promiscuous mode of an interface to off with the following command:

$ sudo ip link set dev <devicename> multicast off promisc off