The recent breach of Drift Protocol was not the result of a traditional hacking incident, but rather a clever exploitation of a legitimate Solana feature known as 'durable nonces.' This feature, designed to enhance transaction convenience, allowed an attacker to pre-sign administrative transfers weeks in advance, ultimately bypassing the protocol's multisig security measures and resulting in the theft of at least $270 million. The attack did not involve a bug in Drift's code, nor did it require the compromise of private keys or the manipulation of oracles.
Instead, the attacker utilized 'durable nonces' to trick Drift's security council into pre-approving transactions that would be executed at a later time, in a context that the signers did not intend. The outcome was a massive drain of funds that took less than a minute to execute, but over a week to set up. To understand how this occurred, it's essential to grasp the concept of 'durable nonces' and their purpose on the Solana network.
Every transaction on Solana includes a 'recent blockhash,' which serves as a timestamp, proving the transaction was created recently. This blockhash expires after approximately 60 to 90 seconds, rendering the transaction invalid if it's not submitted to the network within that timeframe. 'Durable nonces' override this safety feature by replacing the expiring blockhash with a fixed 'nonce,' a one-time code stored in a special on-chain account, keeping the transaction valid indefinitely until it's submitted.
This feature is legitimate and necessary for hardware wallets, offline signing setups, and institutional custody solutions, as it allows them to prepare and approve transactions without being forced to submit them within a narrow 90-second window. However, indefinitely valid transactions pose a significant problem, as they can be executed at any time, according to the system's hardcoded rules, without the ability for the signer to revoke their approval unless the nonce account is manually advanced. The attacker exploited this vulnerability by targeting Drift's 'Security Council multisig,' a system requiring multiple individuals to share control, with any action necessitating approval from at least two members. The attacker did not need to compromise the keys of the council members; instead, they obtained two signatures through 'unauthorized or misrepresented transaction approvals,' where the signers likely believed they were approving routine transactions.
The timeline of the attack, as published by Drift, reveals that on March 23, four durable nonce accounts were created, with two associated with legitimate Drift Security Council members and two controlled by the attacker. This indicated that the attacker had already obtained valid signatures from two council members, locked into durable nonce transactions that would not expire. The attacker adapted to changes in the Security Council configuration, re-obtaining the required two-of-five approval threshold under the new setup. On April 1, the attacker executed the plan, submitting pre-signed durable nonce transactions that allowed them to gain full control of Drift's protocol-level permissions within minutes.
They then introduced a fraudulent withdrawal mechanism, draining the vaults of over $270 million. The stolen funds were transferred through various wallets and exchanges, eventually moving to Ethereum addresses via cross-chain bridges.
The primary drainer wallet was funded eight days before the attack and remained inactive until execution day. The attack highlights the dangers of social engineering and operational security failures in DeFi protocols, as well as the potential risks associated with features like 'durable nonces.' The incident also raises questions about how two separate multisig members approved transactions they did not understand and whether any tooling or interface changes could have flagged durable nonce transactions as requiring additional scrutiny.