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Comment by koeliga | Hacker News Reader

This a known method now of social engineering. See this post from last year: https://news.ycombinator.com/item?id=45591707

Still crazy tho that one dev's compromised device could withdraw 6 billion...

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Multiple wtfs: one dev can access 6B; the dev does job interview from the work laptop; the work laptop has permission to run random executables with it having access to sensitive stuff. Maybe they went on to hack into stuff from the dev's laptop that they should not have had access to.

Of course as usual the legacy media article fails to address that key issue. If I had to guess I'd say that their system uses some sort of HSM to sign chain transactions but there are not strong controls on what txn it will agree to sign. Therefore somewhere in their code there's a place where you can just insert your transaction du jour and it'll go through. Once you have that scenario anyone who can modify the system's code will be able to steal as much money as they want. So the "developer laptop" may have only been used to push a PR or perhaps change code via a more direct route -- publishing a new container image or other build artifact. Using AI tools I think it would be quite feasible to point an agent at the pile of code on that laptop and just ask it "what code do I need to change to allow any transaction to be sent on-chain"? So the attacker didn't need to have deep knowledge of the system.

Edit: Binance has now published some details on the attack. The attacker subverted an EIP-7702 contract rather than as I theorized an HSM authorization process.

7702 made the attack a bit more efficient but wasn’t critical. The core sin was the control plane to submit orders to the MPC signing system (I think it has been reported as MPC vs HSM but largely equivalent here) was not sufficiently isolated, and insufficient preventive controls and alerting on dev machines. But the number one thing for me is that devs could get access to replace signing control systems without a multiple person involved review and approval process. Plus $6.5B or more in assets in that system given that level of controls.

With this architecture honestly surprised a suborned insider didn’t steal the assets before this time. No need for outsiders if individual insiders can instruct a payment to be made.

(It is clear 7702 wasn’t core to this because non-eth systems using the same signing infrastructure were also compromised.)

I had a few long and fairly unpleasant calls with insurance markets over the past few days on this point as we do billion dollar insurance policies for similar risks; would have caught these during underwriting and raised with client and excluded or not issued until fixed.

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