9.1.4. V2X Communication Vulnerabilities

The V2X Ecosystem: A New Attack Surface

V2X is not a single technology but an ecosystem of communication protocols enabling a vehicle to exchange information with its environment. This includes Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I), Vehicle-to-Pedestrian (V2P), and Vehicle-to-Network (V2N). Attacks on V2X target the data in transit, aiming to poison the information an autonomous vehicle uses for critical path planning and decision-making. The two dominant communication standards, DSRC and C-V2X, present different security postures.

Core Attack Vectors in V2X

Your operations will focus on forging, replaying, or suppressing legitimate V2X messages. The goal is to make the target vehicle’s AI perceive a reality of your making, forcing it into unsafe or undesirable actions.

BSM Spoofing: Creating Phantom Obstacles

The Basic Safety Message (BSM) is the heartbeat of V2V communication, constantly broadcasting a vehicle’s position, speed, and heading. By crafting and transmitting malicious BSMs, you can create “ghost vehicles.” These digital phantoms can cause a target vehicle to brake suddenly for a non-existent car, refuse to enter an empty intersection, or trigger its collision avoidance system without cause. The key is to create a believable fiction; a ghost vehicle that teleports or violates physics will be rejected by the vehicle’s plausibility checks.

# Pseudocode for crafting a malicious BSM packet
function create_malicious_bsm(target_vehicle_pos):
    # 1. Define a fake vehicle ID not in use nearby
    malicious_id = generate_random_id()

    # 2. Position the ghost vehicle in the target's path
    ghost_pos_lat = target_vehicle_pos.lat + 0.0001 // Slightly ahead
    ghost_pos_lon = target_vehicle_pos.lon

    # 3. Fabricate believable dynamics (e.g., matching speed)
    ghost_speed = target_vehicle_pos.speed
    ghost_heading = target_vehicle_pos.heading

    # 4. Construct the BSM packet with fabricated data
    bsm_packet = new BSM(
        id: malicious_id,
        latitude: ghost_pos_lat,
        longitude: ghost_pos_lon,
        speed: ghost_speed,
        heading: ghost_heading
    )

    # 5. Sign the packet with a compromised or test certificate
    signed_packet = sign_with_pki(bsm_packet, compromised_key)

    return signed_packet
            

Infrastructure Impersonation: Manipulating the Environment

V2I attacks involve impersonating infrastructure elements like smart traffic lights or road-side units (RSUs). By spoofing Signal Phase and Timing (SPaT) messages, you can tell an autonomous vehicle that a red light is green, luring it into a dangerous intersection. Alternatively, you can create a perpetual red light to cause gridlock. Forging MAP messages, which describe intersection geometry, allows for even more subtle manipulation, such as making a one-way street appear to be two-way in the vehicle’s digital perception.

Sybil Attacks: Manufacturing Consensus

A Sybil attack involves a single attacker creating a large number of pseudonymous identities to overwhelm or manipulate a system that relies on collective input. In a V2X context, you can broadcast BSMs from dozens or hundreds of non-existent vehicles. This can create a phantom traffic jam, causing navigation systems to reroute all nearby autonomous vehicles. This attack tests the system’s ability to handle scale and detect when a large number of “vehicles” are originating from a single physical transmitter.

V2N Exploitation: Attacking the Cloud Link

The Vehicle-to-Network link connects the vehicle to cloud services for teleoperation, over-the-air updates, and high-definition map streaming. This surface is more akin to traditional network penetration testing. Your targets are the APIs, VPNs, and communication protocols that bridge the vehicle and the cloud. A successful compromise could lead to remote control of the vehicle, exfiltration of sensitive telemetry, or a denial-of-service attack that cuts the vehicle off from critical remote support.

Red Team Objectives and Defensive Probes

When testing V2X systems, your goal is not just to demonstrate a single spoofed message. It’s to probe the AI’s trust boundaries and the system’s resilience. Your test plan should seek to answer these questions:

• Data Fusion Dominance: At what point does the vehicle trust V2X data over its own physical sensors? Can a spoofed BSM reporting a stopped vehicle override LiDAR data that shows a clear path? Finding this threshold is a critical objective.
• PKI Robustness: How does the vehicle handle messages with invalid, expired, or revoked certificates? Is the certificate revocation list (CRL) check timely and effective, or can you use a known-bad certificate to inject messages for a period?
• Plausibility Filtering: Test the vehicle’s “sanity checks.” Broadcast BSMs with impossible physics (e.g., extreme acceleration, sudden teleportation). Does the system correctly identify and discard this data, or can it be confused?
• Denial of Service Resilience: Can you overwhelm the vehicle’s onboard unit (OBU) by flooding it with valid but useless V2X messages? This tests rate-limiting and resource management on the communications hardware.