Nuls, a distributed ledger platform declared on Sunday in a tweet that robbers have stolen approximately $480,000 worth of NULS tokens in a hack.

The platform’s operators discovered 2 million NULS transferred, and 548,354 tokens, worth approximately $132,000, have already been posted to trading markets and traded away.

To oppose the theft, the platform declared that it would be administering a “hard fork,” which is a direct code modification of the blockchain itself to transform how it operates that will slay the remaining tokens, making them untradable.

“After the hard fork, the remaining 1451645.65303905 NULS that has not entered the trading market will be destroyed in a permanent freeze to prevent continued flow into the market,” read a statement on the Nuls Twitter account.

The constant freeze of those tokens will limit further losses to the community and ensure that the thieves cannot benefit from the theft. As for the tokens already sold and traded, new owners probably ignorant they were stolen will retain access.

Hard forks to blockchain systems are a contentious method of dealing with thefts. Blockchain technology serves as a permanent historical record of transactions, which is often concentrated on as a proof of trust in the system itself, these sorts of fundamental changes show that blockchain data is not entirely unalterable.

The most notable case of a hard fork used to deal with theft is the Ethereum blockchain Decentralized Autonomous Organization hack. During that theft, hackers stole approximately $55.4 million worth of Ethereum currency.

In reply, the core developer team of Ethereum designed a hard fork that restored the stolen currency and split Ethereum between the current most-used chain and Ethereum Classic.

The Nuls developer team stated the attack happened because of a security vulnerability in NULS version 2.2, which has been settled. To defend against this vulnerability, and support the hard fork, node operators and wallet owners will need to update their software to the next version of NULS or lose access to their currency.

Since the release of the hard fork on Dec. 22, NULS has dropped from $0.249 a token to $0.235 a token. The stolen tokens only represent around 2% of all tradable NULS.

Nuls is an open-source enterprise-grade public blockchain platform created on a modular architecture founded in 2017 by the Singapore-based company NULS Foundation Pte. Ltd. Its vision is to provide a public blockchain that can also be customized to run private blockchains to meet different industrial goals.