Rigged Coding Assignment, Abused AI Tool Opened Path to $6 Billion Binance Heist

What it is

Binance's initial incident report (published 3 November 2026), as relayed by SecurityWeek, gives the intrusion chain behind the $6.34 billion theft that the FBI attributes to North Korea's TraderTraitor group. Binance says about $2.85 billion was frozen or intercepted. Elliptic says about $3.18 billion remained in theft-linked addresses as of 3 November. North Korea rejects the attribution.

How it works

The campaign ran in stages across four months:

• June 2026: A Wallet DevOps engineer searched for a popular AI coding tool and downloaded a tampered Homebrew installation. Binance's security team caught it, swapped the device and reset credentials. By then the attackers had learned what the engineer did and who they worked with.
• September 2026: A second engineer was approached by a fake "project director" and put through two interviews, with a fake HR representative and then a fake CEO of a nonexistent company. The final step was a request to download a coding "assignment" onto the work computer. It hid a malicious repository that ran as soon as the engineer set it up. The malware swapped in a rogue copy of a legitimate developer tool component and opened a channel to an attacker server. Binance says this 0-day malware was not detected by its endpoint protection.
• 20 October 2026: Using the infected machine and an internal AI tool, the attackers took over the first engineer's system and a third wallet engineer's system. The report does not say how the AI tool was used.
• 29 October 2026: The first engineer's machine held a token that allowed container deployments. The attackers logged into the third engineer's computer, deployed a container with the first engineer's credentials, and started the attack with a malicious script.

The attackers then used unauthorized access to an internal wallet signing service to move XRP, SOL, OP and BTC out of hot wallets. The same service was used to abuse Ethereum's EIP-7702, giving an attacker-controlled contract partial execution rights over a hot wallet.

Why containment was hard

Binance states that suspending withdrawals could not stop all movements. The malicious EIP-7702 authorizations lived on-chain and ran independently of its withdrawal infrastructure. Because the hot wallet used MPC, Binance had no single key to cancel the delegation immediately. The last unauthorized transfer settled at 23:56 UTC, and the delegation was cleared shortly after midnight.

What Binance did

It rebuilt the affected wallet system and the AI tool, replaced devices, and retired the engineers' credentials and tokens. It is engaging independent security firms and plans a research fund for AI security in blockchain environments. It also says it blocked 57 suspected North Korea-linked threats this year.

Caveats

This is an initial report, not a final one. It gives no detail on the AI tool's role, the specific developer tool component that was replaced, or how the signing service was accessed without authorization. Attribution to TraderTraitor is the FBI's claim and is denied by North Korea. Elliptic reports the laundering used automation but showed no sign of AI agents making decisions.