You need to capture the flag, or rather to put Ether in the Flag
contract without a Thief
taking it before you can claim the flag.
- The exercise serves to show that not all Ether comes with a beautiful transaction.
- It also serves to show that if you forgot to make your operations atomic, someone may exploit it by sneaking in between your operations.
- Accessorily it shows the power of gas price.
- You need to run the
node/watchAndSteal.js
trap for the challenge to be fun. - The
Thief
contract is not strictly needed, it is only here so that thecapture
call happens in an internal transaction, and as such is semi-invisible on Etherscan. - The
sneakUpOn
function is totally useless and acts as a decoy. Do not remove it.
When deploying the IPFS page, you need to adjust, manually?, for ./static
and ../../fonts
.
Current IPFS location: http://ipfs.b9lab.com:8080/ipfs/QmNidcNaGnresM8EFhU5J3gWV9Sfan5CX3qwcTfruNJN8x/