I am seeking to better understand the bZx exploit by following the Internal Transaction section of the exploit transaction on Etherscan click here to view.

I am confused about what the Type Trace Addresses mean.

How do I interpret call_0_0_0_3_0_0_0 or call_0_0_0_3_0_6_0_5_0_5_0_2_2_3_7?

  • 1
    It seems that a number is the call order and how many numbers is how nested is the call, ie call_2 is the third call, call_0_1 will be the second call nested into the first one. Etherscan only shows internal transactions that transfer ethers.
    – Ismael
    Commented Feb 28, 2020 at 12:51
  • My goal is to discover the specific functions that were called in each contract during the bZx attack transaction. Originally, i thought that using the Internal Transaction section of Etherscan was the ideal method to achieve this goal. This no longer seems to be the case. If I wanted to determine the exact functions that were called during this attack, what would be the best method to figure this out. Commented Feb 28, 2020 at 20:41
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    There are some tools that are better for doing that for example ethtx.info/mainnet/…
    – Ismael
    Commented Feb 28, 2020 at 20:49

1 Answer 1


These are transactions that are called by a contract... Meaning, normally, a user calls a contract and the contract does something. In a normal situation, the contract gives you back tokens or ETH. In some contracts, the contract interacts with other contracts, meaning the contract called itself calls other contracts (this is an internal call). And sometimes these internal interaction results in ETH being transferred around between contracts or addresses. This kind of transactions between contracts with some ETH transferred are the ones you see on the main page of the etherscan under the "To" heading, but under internal transactions page in Etherscan you see all internal calls (meaning internal contract calls with ETH transfers and those without any transfers).

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