> For the complete documentation index, see [llms.txt](https://ret2basic.gitbook.io/ctfwriteup/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ret2basic.gitbook.io/ctfwriteup/web3-ctf/quillctf/invest-pool.md).
# Invest Pool
## Idea
### Part 1: initialize the pool with the password
A hint for password:
```solidity
// Password could be found in Goerli contract
// 0xA45aC53E355161f33fB00d3c9485C77be3c808ae
// Hint: Password length is more than 30 chars
```
This address does not expose password in any state variable, but we can find something in its metadata. Use this site to extract metadata:
{% embed url="" %}
Here we can find an ipfs address. Click that "View on IPFS" button:
Password is:
```solidity
j5kvj49djym590dcjbm7034uv09jih094gjcmjg90cjm58bnginxxx
```
### Part 2: exploit first depositor inflation attack
Note that we can pass the assertion by stealing just a little bit of tokens:
```solidity
assertGt(token.balanceOf(hacker), hackerBalanceBeforeHack);
```
Also there is a helper function in the provided PoC template:
```solidity
function userDeposit(uint amount) public {
vm.prank(user);
pool.deposit(amount);
vm.stopPrank();
}
```
It should be crystal clear that the intended attack is the "first depositor inflation attack". The idea of that attack is:
* attacker deposits 1 wei to get 1 share as the first depositor
* attacker send a lot of tokens to the pool to inflate the share (I think of this as "sacrifice" some tokens to inflate the share)
* victim user deposits some money into the pool
* attacker withdraws that one share. It worths more than expected because the share was inflated. A portion of victim user's deposit will become attacker's profit.
## PoC
{% embed url="" %}
