Cisco NX-OS
TMA-CISCO-NXOS-3.2.4
Disable IP Directed Broadcasts on all Layer 3 Interfaces
Description
An IP directed broadcast is an IP packet whose destination address is a valid broadcast address for an IP subnet, but which originates from a node that is not itself a part of that destination subnet. Directed broadcasts can be abused in several ways: - a volumetric DOS attack against the NX-OS switch itself, the sent volume of data can be much larger than the received request - a volumetric DOS attack against a third party (often called a "smurf attack") ... CIS marks this Manual; directed broadcast only appears in the config when enabled. Audited against the output of 'show running-config' (run 'terminal length 0' first; do not use 'show running-config all', which adds default values).
How it is checked
Audit method: Configuration pattern
- Pattern
(?m)^[ \t]+ip directed-broadcast\b
How it is fixed
Fix method: Guidance or infrastructure patch
no ip directed-broadcast
Properties
- Operating systems
- Any
- Tags
- cisco-nxosnetworkhardening
- Reference
- CIS Cisco NX-OS Benchmark v1.2.0 - 3.2.4 Disable IP Directed Broadcasts on all Layer 3 Interfaces
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
tmaegis scan --target cisco-nxos