The Drift Protocol attack was unconventional, as it didn't involve exploiting a bug or cracking a private key. Instead, the attacker utilized Solana's 'durable nonces' feature, which allows for the pre-approval of transactions that can be executed at a later time, bypassing the protocol's multisig security measures. This feature, designed for convenience, enabled the attacker to trick Drift's security council into pre-approving transactions that would be executed weeks later, in a context the signers never intended. As a result, at least $270 million was drained from Drift in under a minute, although the setup took over a week.
The 'durable nonces' feature exists to override Solana's safety mechanism, which typically renders transactions invalid after 60 to 90 seconds if they are not submitted to the network. By using a fixed 'nonce' stored in a special on-chain account, transactions can remain valid indefinitely until someone chooses to submit them.
This feature is necessary for legitimate reasons, such as hardware wallets, offline signing setups, and institutional custody solutions, which need to prepare and approve transactions without being forced to submit them within a short time frame. However, this creates a problem, as indefinitely valid transactions can be executed at any time, and the signer has no way to revoke their approval unless the nonce account is manually advanced.
In the case of Drift, the attacker exploited this feature by obtaining two signatures from the security council, which were then used to execute malicious administrative transfers. The attack was possible because the attacker did not need to compromise anyone's keys; they only needed two signatures, which they appear to have obtained through 'unauthorized or misrepresented transaction approvals.' The timeline of the attack shows that the attacker created durable nonce accounts associated with legitimate Drift Security Council members and their own accounts, allowing them to obtain valid signatures that would not expire. The attacker then adapted to changes in the security council and eventually executed the attack, draining the vaults and introducing a fraudulent withdrawal mechanism. On-chain researchers tracked the stolen funds, which totaled roughly $270 million across dozens of tokens.
The primary drainer wallet was funded eight days before the attack, and the stolen funds were transferred to intermediary wallets and eventually to Ethereum addresses via Wormhole, a cross-chain bridge. The attack highlights the dangers of social engineering and operational security failures in DeFi protocols, which are increasingly becoming the primary means by which money is stolen.
The use of durable nonces in this attack is particularly concerning, as it exploits a feature that exists for legitimate reasons and is difficult to defend against without fundamentally changing how multisig approvals work on Solana.