Hacker Exploited Binance Bridge; Stole 2M BNB Tokens ($556 Mn)

    Pathik Bhattacharya
    Pathik Bhattacharya
    Published on October 7, 2022 11:26 AM

    Updated on January 25, 2023 5:33 PM

    Binance cross chain compromised with over 2 Million BNB Tokens.
    Hacker Exploited Binance Bridge; Stole 2M BNB Tokens ($556 Mn)

    Attackers have again targeted a bridge chain and this time, it's none other than Binance Chain.

    When we were busy with our day-to-day life, someone vanished 2 Million BNB tokens from the BSC chain.

    Simulating the Hacker's Mind

    The exploit was reported by a twitter user with user name samczsun who's a self proclaimed security researcher. 


    "It all started when someone on twitter with username @zachxbt sent the address of the transaction. And to his surprise, the amount was massive," He stated. 

    Stolen Funds Found on Venus Protocol

    The hacker deposited over $200 Mn on Venus Protocol but the challenge was to trace out from where the exploiter got all of the funds. 

    Interestingly, it was found that however the attacker breached the Binance cross-chain and took out 1 Million BNB twice. 

    Samczsun instantly noticed that the block height which is basically used to determine the specific location of that certain block in the blockchain is almost the same both times he breached the chain. 

    It was also noted that the proof of transaction was also shorter than the normal validated transaction the attacker used to validate his transaction. 

    With a lot of other technicalities which are beyond one normal person's understanding until and unless he/she is a cyber security expert, the hacker was well trained on these bridge-chain swaps before committing the hack.

    Uniting All Aspects

    Summing up all the stuffs, samczsun tweeted how the things could be done simply (which isn't so simple)

    "We'll take a legitimate proof and modify it so that:

    1) we add a new leaf for our forged payload 2) we add a blank inner node to satisfy the prover, 3) we tweak our leaf to exit early with the correct root hash"  

    The security researcher said that the hacker may have used a different method and operations to breach the blockchain because the proof address was shorter than normal. Although, he also claimed that most of the exploit was identical as per his analysis. 

    Binance Took Instant Action

    Soon after the news spreaded, Binance suspended all its BSC transactions. 

    Changpeng Zhao, CEO of Binance, addressed the issue once the suspicious activity was discovered and insisted that the money was secure. He eventually acknowledged that the impact estimate was near about $100 million USD. According to sources, the attack caused the loss of BNB tokens worth more than $600 million.

    Still funds worth $7 Million have been frozen by the attacker which is yet to be recovered. 

    Since then, the BSC Validators have done a great job to recover the stolen money and for the time being, the BSC chain is working properly as confirmed by Cz Zhao.