How Hackers Use Flipper Zero to Open Hotel Doors

In today’s digital age, hotel room security heavily relies on electronic locks and wireless access systems. While these technologies offer convenience and improve the guest experience, they also introduce new risks.

Devices like the Flipper Zero, a compact, multifunctional hacking tool, have exposed critical vulnerabilities in these systems. Understanding these risks is essential for hotel owners, security professionals, and travelers alike.

This article explains how hackers exploit hotel locks, highlights real-world incidents, and provides actionable advice for safeguarding hotel rooms and personal security.

The Flipper Zero is a portable cybersecurity device created for ethical hackers and penetration testers. It interacts with RFID cards, NFC chips, sub-GHz devices, Bluetooth signals, and infrared systems.

With the ability to read, copy, and emulate digital signals, Flipper Zero is powerful for security research but poses a threat when misused. Its capabilities allow it to exploit vulnerabilities in outdated or poorly protected hotel lock systems, posing risks for botth guests and hotel operators.

Hotels that continue to use magstripe keycards are vulnerable to security breaches. These cards store unencrypted data that can be cloned with inexpensive skimming devices. Although Flipper Zero cannot directly read magnetic stripes, obtained data can easily be replicated. Relying on magstripe technology puts hotels at high risk for unauthorized room access.

Older 125 kHz proximity cards transmit a static ID without encryption, making them highly vulnerable. Devices like Flipper Zero can read and clone these cards within seconds, granting unauthorized access to rooms or restricted areas. Many hotels have transitioned to newer technologies, but some older properties may still use these insecure systems.

Modern hotels use NFC-based cards like MIFARE Classic, MIFARE Ultralight, or MIFARE DESFire. While newer smart cards offer better security, the MIFARE Classic has known cryptographic flaws. Flipper Zero, when paired with custom firmware, can crack and emulate these cards if the encryption keys are weak or improperly managed, effectively bypassing hotel security.

An increasing number of hotels use mobile key apps that allow guests to unlock rooms via smartphones. Although generally secure, vulnerabilities in Bluetooth Low Energy (BLE) communication or backend servers can still exist. Flipper Zero cannot directly hack BLE locks, but attackers with more advanced tools might target these mobile systems.

• Onity Lock Hack (2012): Researcher Cody Brocious demonstrated that $50 worth of hardware could unlock millions of Onity locks worldwide, later exploited by criminals for hotel thefts.
• F-Secure VingCard Master Key Hack (2018): Researchers created master keys for Assa Abloy locks using discarded or expired guest keycards, exposing massive security flaws.
• Dormakaba “Unsaflok” Vulnerability (2024): Hackers exposed flaws in Dormakaba Saflok systems that allowed the creation of master keys using any hotel-issued card, with Flipper Zero capable of facilitating such attacks.

• Keycard Cloning: Flipper Zero can scan and emulate RFID keycards effortlessly, enabling unauthorized room access.
• Master Key Generation: In systems with flawed encryption, hackers can derive master keys to unlock any room in a property.
• Replay and Brute Force Attacks: Although less common, Flipper Zero can attempt brute-force attacks on systems with predictable key IDs, gaining unauthorized access.

Hotels should phase out magstripe and 125 kHz RFID systems and adopt secure, encrypted solutions like MIFARE DESFire EV2, which offer dynamic key management and strong encryption.

Manufacturers frequently release security patches for lock systems. Hotels must routinely update firmware to fix known vulnerabilities and maintain robust defenses.

Strict protocols around master key management, including regular audits, expiration policies, and limited access, are critical to reducing security risks.

Using multifactor authentication methods, such as PINs or mobile confirmations for master key usage, significantly increases lock system security without overly burdening guests.

Regular staff training on recognizing suspicious behavior, safeguarding physical keys, and swiftly reporting anomalies can prevent unauthorized access attempts.

Treat your keycard like a credit card. Store it in an RFID-blocking sleeve or wallet to prevent wireless scanning by malicious devices.

Always engage deadbolts or secondary locks inside your room. These simple measures provide an extra barrier against unauthorized entry.

Be vigilant in hallways and public spaces. Report any suspicious behavior or signs of tampered locks to hotel management immediately.

After your stay, return your keycard to the front desk or destroy it to prevent misuse. Discarded keycards can still contain data valuable to attackers.

When available, choose secure mobile key options. Ensure your smartphone is protected with a strong password or biometric security to safeguard mobile access credentials.

Devices like the Flipper Zero highlight the vulnerabilities present in outdated hotel lock systems, emphasizing the urgent need for action from hotel operators and travelers. Hotels must prioritize upgrading to modern, encrypted systems, maintain strong key management, and stay up-to-date with firmware updates to ensure guest safety. In this evolving landscape, it’s crucial to adopt measures that prevent Smart door lock vulnerabilities from being exploited.

For travelers, adopting simple protective measures can significantly reduce exposure to unauthorized access. Treating your hotel keycard with the same care as your valuables, using extra room locks, and staying alert can make all the difference.

As technology continues to advance, so must our approach to securing digital and physical spaces. Awareness, vigilance, and proactive strategies ensure a safer and more secure travel experience for everyone.