ETH & STRK Bridge Withdrawals: Enhancing the Efficiency of the Withdrawal Limit Safeguard
As part of its continued commitment to user safety and ecosystem resilience, the Starknet Security Council (SC) is about to upgrade the L1 and L2 Withdrawal Limit safeguard on the ETH and STRK bridges to make it both more effective and more responsive. The SC would appreciate ecosystem feedback before moving forward.
How the Mechanism Currently Works
The SC is the current securityAdmin for both the ETH and STRK bridges. The securityAdmin can assign a securityAgent — a role with a single permission: To enable the Withdrawal Limit function.
When enabling this function on a bridge, the daily withdrawals are limited to 5% (L1) and 8% (L2) of the TVL, per token (Daily - i.e. within 00:00 to 23:59 window, GMT). After the limit has been reached, withdrawals will fail. Once the date changes, the user can retry to execute them.
The securityAdmin can disable the Withdrawal limit with 3 multisig approvals.
Currently, StarkWare is assigned as the securityAgent on both ETH and STRK bridges, on L1 and L2.
What’s Changing?
To improve responsiveness, the SC proposes adding Hypernative as an automated securityAgent, alongside StarkWare in the ETH and STRK bridge contracts, both on L1 and L2.
Hypernative is a real-time monitoring, risk detection, and automated response solution that proactively secures blockchain ecosystems. The Hypernative platform accurately identifies threats like sequencer vulnerabilities, bridge exploits, governance attacks, and malicious smart contracts deployed on-chain, offering precious minutes to respond and maintain the integrity and trust of the network.
The withdrawal limit will be activated based on monitoring of the protocol’s well-being – an aggregation of L1 and L2 events and additional metrics that ensure the validity of each transaction in the protocol.
Why now?
Over the past 7 months, the Hypernative monitoring solution was tested with no false-positive alerts observed. This proven reliability provides confidence about using Hypernative as an automatic trigger to further enhance the security of the ETH and STRK bridges.
The threshold suggested — 5% on L1 and 8% on L2
Withdrawal patterns since July 2024 have been analyzed to identify a balanced threshold that ensures proactive protection while minimizing disruption to normal bridging activity. For STRK, daily withdrawals have consistently remained well below the 5% threshold. For ETH, only two isolated days slightly exceeded this level. These findings indicate that the suggested daily limit maintains a very low risk of interfering with typical bridge usage.
Your input is needed
This proposal is part of the SC’s broader commitment to safe, transparent, and community-driven bridging on Starknet. The SC invites feedback from the Starknet ecosystem. If you have questions, thoughts, or concerns, please share them in this thread. We’ll collect and respond to feedback over the next 7 days, and your input will directly shape how the SC moves forward.
— The Security Council