A new report by Bybit’s Lazarus Security Lab has revealed that 16 major blockchains include code that allows them to freeze or restrict user funds.
The report, titled “Blockchain Freezing Exposed: Examine The Impact of Fund Freezing Ability in Blockchain,” is the first large-scale analysis of how blockchains can intervene in user transactions to contain security incidents such as hacks and exploits.
The report examined 166 blockchain networks using an AI-driven analysis combined with manual review. Researchers found that while 16 chains currently have freezing functions, another 19 could introduce them with relatively minor protocol changes.
The report identifies three distinct types of fund-freezing mechanisms:
Hardcoded freezing, built directly into the blockchain code (e.g., BNB Chain, VeChain)
Configuration-based freezing, managed through validator or foundation settings (e.g., Sui, Aptos)
On-chain contract freezing, executed via system contracts (e.g., HECO)
The study highlights several notable cases:
Sui froze $162 million in stolen assets after the Cetus hack.
Aptos later added blacklisting functions following the incident.
BNB Chain used hardcoded blacklists to contain a $570 million bridge exploit.
VeChain set an early precedent in 2019 by freezing funds from a $6.6 million breach.
Cosmos’s modular account design may enable similar interventions in the future.
These interventions demonstrate how fund-freezing functions can serve as emergency tools to protect users and mitigate damage in large-scale security breaches.
“Blockchain was built on the principle of decentralization — yet our research shows that many networks are developing pragmatic safety mechanisms to respond quickly to threats," said David Zong, Head of Group Risk Control and Security at Bybit. “At Bybit, we believe transparency builds trust. Our goal is to encourage open dialogue and better governance across the industry. ”
To conduct the review, Bybit’s Lazarus Security Lab built an AI-assisted detection framework to scan codebases for modules enabling blacklisting, transaction filtering, or dynamic configuration updates. Human researchers then validated each case to ensure accuracy.
The study concludes that transparency around emergency intervention mechanisms should become a core pillar of blockchain governance, urging projects to publicly disclose whether and how they can intervene in on-chain activity.
“As crypto matures, clear and transparent safety mechanisms will help build lasting trust among users and institutions,” the study concludes.
The full research, “Blockchain Freezing Exposed: Examining the Impact of Fund Freezing Ability in Blockchain,” is available here.
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