Understanding Lock Freezing Attacks: A Guide to Enhancing Your Security

Lock freezing is a method of forced entry used to bypass the security features of locks, particularly anti-snap euro cylinder locks. This method exploits the properties of water and ice to jam the internal mechanisms of an anti-snap lock, making it operable even after a lock snapping attempt. Understanding how lock freezing works and how to protect against it is crucial for enhancing your home or business security.

What is a Lock Freezing Attack?

A lock freezing attack aims to gain unauthorised access by bypassing the extra security features of anti-snap locks. Anti-snap cylinder locks feature sacrificial sections that break away during a lock snapping attempt, which can prevent the lock from being accessed. In addition, many anti-snap locks use a retaining pin, or immobiliser, that shoots into the cam when the sacrificial section is broken away. This holds the cam in place and prevents the lock from being manipulated.

Lock freezing attacks target this retaining pin or immobiliser by using ice to prevent it from deploying. Lock freezing involves injecting water into a euro cylinder lock and then using a freezing agent, such as a refrigerant spray, to turn the water into ice. The ice formation jams the lock’s internal components, including the immobiliser, preventing them from functioning properly. This allows the attacker to manipulate or break the lock more easily.

The Lock Freezing Process

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  • Injecting Water: Once the attacker has broken the door's handle or escutcheon to expose the lock's front section, water is injected into the lock through the keyway using a syringe or other implement. The aim is to fill the internal components of the lock with water.
  • Applying the Freezing Agent: A refrigerant spray, usually a compressed air canister turned upside down, is used to expel super-chilled liquid. This liquid is sprayed into the keyway, causing the injected water to freeze rapidly. The resulting ice formation can jam the internal mechanisms of the lock, including the retaining pin.
  • Snapping the Lock: Grips or locking pliers are used to snap the front section of the lock. Normally, the retaining pin would activate, immobilising the cam and preventing it being turned. However, the ice may have jammed this security mechanism, rendering it ineffective.

Unlocking the Door: With the lock's front section removed and the internal security mechanisms jammed, the attacker can more easily manipulate the remaining parts of the cylinder to unlock the door.

Euro Cylinder TS007 Master Key Systems

How to Prevent Lock Freezing Attacks

The best way to defend against lock freezing attacks is to use high-quality locks that have been tested and proven to resist this technique.

Lock freezing is a relatively new method of forced entry that is used to bypass even anti-snap locks. However, as break-in techniques evolve, so do security standards and tests. The 2024 security checks for 3-star euro cylinders now test against lock freezing attacks and will be used for Secured by Design, PAS24 and Sold Secure Diamond standards.

According to the MLA, lock freezing tests will be mandatory for 2026, so preparing early and checking your cylinders pass these tests is highly recommended.

Pending a factory modification, Master Key Systems’ own Adapta Prime HS TS007 3 Star euro cylinder locks have already passed this test, meaning they offer protection against lock freezing attacks, as well as a host of other security threats.

For the ultimate peace of mind, ensure your home or property is equipped with 3-star door cylinders that have passed these latest tests, particularly on vulnerable or common entrances. For more information, feel free to get in touch with the Master Key Systems team who will be happy to advise further on these new standards and related door hardware.

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