2026-09-10 –, Großer Saal
Smart locks are rapidly replacing physical keys, but trusting your front door to an IoT device still comes with significant risks. In this talk, we will dissect the highly rated SwitchBot Lock Pro and demonstrate how a classic cryptographic implementation flaw allowed anyone to silently unlock the door without an physical tampering. By reverse-engineering the firmware and analyzing the custom Bluetooth Low Energy (BLE) protocol between the outdoor keypad and the indoor actuator, we discovered the system relies on AES in Counter (CTR) mode with zero integrity checks. We will demonstrate how we exploited this to create a universal, software-only UNLOCK payload. Join us as we showcase the live exploit, break down the vendor's flawed patch, explain how backward compatibility significantly delayed the patch, and celebrate our massive 100€ bug bounty.
While selecting targets for a team IoT hacking event, the SwitchBot Lock Pro Combo stood out: it is one of the most sold smart locks on the market, offering PIN, fingerprint, NFC, and app-based entry. The hardware consists of an indoor actuator that turns the physical key and an outdoor keypad. However, our initial recon of the Android app revealed, that the outdoor keypad holds the decision-making logic and sends execution commands to the indoor actuator over unprotected BLE, relying entirely on a custom application-layer encrypted protocol.
Diving deeper into this custom protocol, we discovered a fatal cryptographic failure. The devices negotiate a secret key and a nonce, but they encrypt their commands using AES in Counter (CTR) mode. Because CTR mode turns a block cipher into a stream cipher and lacks any integrity protection (like a MAC), bit-flips in the ciphertext propagate directly to the plaintext upon decryption without an opportunity to detect the manipulation.
In this 30-minute presentation, we will walk the audience through how we weaponized this exact flaw. Because a keypad's LOCK button always broadcasts an encrypted command, an attacker only needs to sniff it. We will explain the math behind our "master key", which only required a pre-computed XOR between encrypted LOCK and UNLOCK commands that is identical across all sessions and locks. By simply applying this to any sniffed LOCK ciphertext, we can instantly forge a valid UNLOCK command and open the door. We will give a live demonstration of this software-only attack in action.
Finally, we will detail our responsible disclosure journey, which serves as a perfect case study in the difficulties of patching IoT ecosystems. The vendor's initial beta patch attempted to add a 2-byte truncated MD5 "YOLO hash" for integrity verification. However, because updating the entire ecosystem takes time, the lock still had to accept legacy commands from the smartphone app. We will show how we trivially bypassed the new patch by simply spoofing the smartphone app, ignoring the checksum entirely.
Kolja is a Security Researcher and Trainer at Neodyme. He specializes in Windows and Active Directory security. He has found vulnerabilities in widely used security products and has extensive exploit development, pentesting, and red teaming experience.