Binance says the attackers behind the roughly $6.34 billion theft from its hot wallets on October 29 used an internal AI tool nine days earlier to “gain control over” two engineers who worked on its wallet systems. The exchange called that step a “springboard” in an initial incident report published on November 3. The report does not name the tool or explain how it was abused.
The report traces the campaign to June, when a wallet DevOps engineer downloaded a tampered Homebrew installation while trying to install “a popular AI coding tool” found through a search engine. Binance detected the anomaly, replaced the device and rotated the related credentials, but says the engineer’s role and wallet infrastructure colleagues had been exposed to the attacker.
In September, someone posing as a project director approached a second engineer through a legitimate job platform. After two rounds of interviews with a fictitious company, the engineer was told to download an “assignment” to a work computer. Its code replaced the pyenv development tool with a malicious version. Binance says endpoint security tools did not detect the malware, which it describes as a zero-day.
On October 20, working from that computer, the attacker used the internal AI tool to gain control over the first engineer and a third, a wallet software engineer, and found a container deployment permission token on the first engineer’s computer. On October 29, the attacker logged on to the third engineer’s computer, used the first engineer’s stolen credentials, deployed a container and ran a malicious script.
Binance says the attacker exploited unauthorized access to an internal wallet signing service to start transactions outside its normal withdrawal process. From 20:05 to 20:09 UTC, five hot wallets sent 233.46 million XRP to an attacker-controlled address, followed by transfers of SOL, OP and 18,270 BTC. The attacker then used the signing service to exploit Ethereum’s EIP-7702 authorization mechanism, giving an attacker-controlled smart contract partial execution rights over a hot wallet. Suspending withdrawals did not invalidate those on-chain authorizations, and because the wallet used multi-party computation, no single private key could revoke them immediately. The final transfer finalized at 23:56 UTC, and Binance cleared the delegation at 00:10 UTC on October 30.
About $2.85 billion has been frozen or intercepted. Binance says it will absorb the loss and had replenished 98 percent of the affected token assets by October 31. On that date the FBI attributed the theft, which it put at more than $6 billion, to the North Korean activity it calls TraderTraitor.
Chainalysis, which puts the total at $6.4 billion and calls it the largest crypto theft in history, says it has attributed more than $14.3 million in losses over the past 18 months to similar North Korean fake-interview and malware schemes. The firm has said a separate intrusion into its own systems was unrelated to the Binance theft. Binance says it detected and prevented 57 suspected North Korea-linked cases this year. A different North Korean group, Kimsuky, ran open-weight models on its own attack servers, the security firm Genians reported in August.
The report does not say what the internal AI tool could access, whether the attacker gave it instructions or whether it took any action on its own. Binance says some technical details will remain confidential and that independent security firms will review its findings. It says it has rebuilt the affected AI tool and its access controls, and is working on a security research fund with AI companies and others.
Sources: Binance, FBI, Chainalysis
–
By the Control Plane Editorial Team