Taking control of a UAV is often the ultimate objective of a physical systems red team engagement. While previous sections covered disrupting navigation or swarms, hijacking implies a complete transfer of authority from the legitimate operator to you. This isn’t just about making the drone crash; it’s about making it yours, redirecting its mission, exfiltrating its sensor data, or turning it into a kinetic weapon against a different target.
Success hinges on identifying and exploiting a weak link in the chain of command, which extends from the operator’s Ground Control Station (GCS) through the radio frequency link to the drone’s onboard flight controller and its autonomous decision-making logic.
The Hijacking Attack Surface
A UAV’s attack surface for remote takeover can be broadly divided into three domains: the control link, the onboard network systems, and the autonomous logic itself. Each requires a distinct set of tools and methodologies.
Key Hijacking Vectors
- Command and Control (C2) Link Interception: The most direct route. If you can speak the drone’s language over its radio link, you can command it. This involves attacking the RF layer.
- Onboard System Compromise: Many advanced drones run a Linux-based OS on a companion computer. If you can gain access via an exposed network service (like Wi-Fi or cellular), you can often bypass the C2 link and issue commands directly to the flight controller.
- Autonomous Logic Manipulation: A more subtle approach. You don’t take over the controls directly; instead, you feed the drone’s AI misleading sensor data, causing its autonomous systems to guide it to a location of your choosing. This was touched upon in navigation exploitation but is perfected as a hijacking technique here.
Tooling for C2 Link Exploitation
The C2 link is a prime target. Most commercial and many custom drones use proprietary protocols over common frequency bands (e.g., 2.4 GHz, 5.8 GHz). Your first step is to analyze this link, and for that, Software-Defined Radio (SDR) is indispensable.
| Attack Type | Description | Common Tools | Primary Defense |
|---|---|---|---|
| Replay Attack | Capture a valid command (e.g., “return to home”) and re-transmit it later to force an action. | HackRF One, GNU Radio, Universal Radio Hacker (URH) | Rolling codes, command counters, or time-based nonces. |
| Command Injection | Reverse engineer the protocol to craft and transmit new, malicious commands. | SDR, Scapy (for packet crafting), custom scripts | Authenticated and encrypted C2 link (e.g., AES-GCM). |
| C2 Jamming & Takeover | Jam the legitimate operator’s signal while simultaneously injecting your own stronger signal to the drone’s receiver. | High-power SDR/jammer, directional antenna | Frequency Hopping Spread Spectrum (FHSS), robust fail-safes. |
| Wi-Fi Deauthentication | For Wi-Fi controlled drones, force the drone to disconnect from the operator and connect to your rogue access point. | Aircrack-ng suite, MDK4 | WPA3, management frame protection (802.11w). |
Crafting malicious packets requires understanding the protocol structure. After capturing traffic with a tool like GQRX or URH, you might use a library like Scapy in Python to build your own packets for injection.
# Pseudocode using a Scapy-like library for command injection
# Assumes the C2 protocol structure has been reverse-engineered
from uav_protocol import UAVPacket, CommandLayer
# Craft a malicious command payload
# Target waypoint coordinates are chosen by the attacker
malicious_payload = CommandLayer(
cmd_type=0x01, # 0x01 might mean "GOTO_WAYPOINT"
seq_num=1337, # Sequence number to track command
latitude=34.0522,
longitude=-118.2437,
altitude=100
)
# Build the full packet with header, checksum, etc.
packet = UAVPacket() / malicious_payload
packet.calculate_checksum()
# Transmit the packet using an SDR interface
sdr_interface.send(packet)
This example simplifies the process, but the principle holds: you build a packet that looks legitimate to the drone’s flight controller but contains your instructions.
Scenario: The “Man-in-the-Middle” Mission Hijack
Let’s walk through a common red team scenario involving a drone that receives mission updates over a Wi-Fi link from its GCS. The goal is to divert the drone from its surveillance path to a designated exfiltration point.
- Reconnaissance: You identify the drone is connecting to a GCS over an open or WEP/WPA2-PSK encrypted Wi-Fi network. You use a tool like `airodump-ng` to capture the handshake to crack the password offline.
- Establish MitM Position: You set up a rogue access point with the same SSID and a stronger signal than the legitimate GCS network. Using `aireplay-ng`, you send deauthentication packets to the drone, forcing it to disconnect from the GCS and reconnect to your rogue AP.
- Intercept and Inject: Now, all traffic between the GCS and the UAV flows through your machine. You use a tool like `mitmproxy` or a custom Scapy script to inspect packets in real-time. When you see a packet containing mission commands (e.g., new waypoints), you modify its payload to insert your malicious coordinates before forwarding it to the drone.
The drone’s AI, having no reason to distrust the digitally signed (or, more likely, unsigned) command, dutifully updates its flight plan and proceeds to your location. You have achieved a mission hijack without ever breaking the C2 protocol’s encryption, if any existed.
Defensive Strategies Against Hijacking
As a red teamer, your findings should lead to actionable defensive recommendations. Preventing remote hijacking requires a defense-in-depth approach.
- Harden the C2 Link: This is paramount. Use strong, authenticated encryption like WPA3 for Wi-Fi or custom protocols built on AES-256-GCM. Implement robust anti-replay mechanisms like sequence numbers combined with a message authentication code (MAC). Frequency hopping adds another layer of difficulty for attackers.
- Secure Onboard Systems: Treat the drone’s companion computer like any other critical server. Disable unused services, change default credentials, implement a firewall, and use secure boot to ensure firmware integrity.
- Implement AI-based Sanity Checks: The drone’s autonomous system shouldn’t blindly trust its inputs.
- Sensor Fusion: Cross-validate data from multiple sensors. If the GPS suddenly reports a location that is physically impossible given the IMU’s accelerometer data, flag the GPS input as untrustworthy.
- Mission Validation: Pre-load mission parameters, including operational boundaries (geofences) and maximum allowable flight vectors. Any new command that violates these rules should be rejected or require manual operator override.
- Behavioral Monitoring: An onboard AI can monitor the drone’s behavior against its expected mission profile. A sudden, sharp deviation from the planned route without a corresponding operator command could trigger a fail-safe, such as returning to the last known-good waypoint.