First-Hop Redundancy Protocols (HSRP/VRRP)¶

1. Compromise HSRP Group (OR)

    1.1. Spoof HSRP Messages (OR)

        1.1.1. Forge Hello Packets (Take Over Active Router Role)

        1.1.2. Modify Priority/Preemption Values

    1.2. Exploit Weak Authentication (OR)

        1.2.1. Crack Plaintext/MD5 Authentication

        1.2.2. Bypass Authentication (If None Configured)

    1.3. Cause Failover Disruption (OR)

        1.3.1. Trigger Unnecessary Active-Standby Switches (DoS)

        1.3.2. Send Fake Resign Messages (Force Role Changes)

2. Man-in-the-Middle (MITM) Attacks (AND)

    2.1. Redirect Traffic via HSRP Takeover (AND)

        2.1.1. Become Active Router (Required)

        2.1.2. Intercept/Modify Traffic (Required)

3. Denial-of-Service (DoS) (OR)

    3.1. Flood HSRP Groups (OR)

        3.1.1. Send Excessive Hellos (Disrupt Election)

        3.1.2. Advertise Invalid Virtual IPs (Confusion Attack)

1. Compromise VRRP Group (OR)

    1.1. Spoof VRRP Advertisements (OR)

        1.1.1. Forge Master Router Advertisements

        1.1.2. Manipulate Priority Values

    1.2. Exploit Authentication Weaknesses (OR)

        1.2.1. Crack Simple Text/MD5 Authentication

        1.2.2. Exploit No Authentication (Default in VRRPv2)

    1.3. Disrupt Failover (OR)

        1.3.1. Force Unnecessary Master-Backup Transitions

        1.3.2. Send Fake Shutdown Events

2. Traffic Interception (AND)

    2.1. MITM via VRRP Takeover (AND)

        2.1.1. Become Master Router (Required)

        2.1.2. Redirect Traffic to Attacker Node (Required)

3. Denial-of-Service (OR)

    3.1. Flood VRRP Groups (OR)

        3.1.1. Overwhelm with Advertisements (Prevent Election)

        3.1.2. Advertise Conflicting Virtual IPs