Rust Fund

AI First Flight #9
Beginner FriendlyRust
EXP
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Submission Details
Severity: high
Valid

withdraw() has no goal check — creator can drain funds even when campaign falls short of target

Root + Impact

Description

  • withdraw() transfers fund.amount_raised to the creator without checking that the fundraising goal was met. A creator can drain all contributions the moment any SOL arrives, regardless of whether the campaign reached its stated target.

pub fn withdraw(ctx: Context<FundWithdraw>) -> Result<()> {
let amount = ctx.accounts.fund.amount_raised;
// No: require!(fund.amount_raised >= fund.goal, ErrorCode::GoalNotMet)
// ...transfer logic...
}

Risk

Likelihood: Any campaign creator can exploit this unconditionally — no special setup required beyond having at least one contributor.

Impact: Contributors lose their SOL permanently. The core crowdfunding guarantee — "funds are only released when the goal is met" — is entirely unenforced on-chain.

Proof of Concept

withdraw() reads amount_raised and transfers immediately — fund.goal is declared but never read inside the function:

grep -n "pub fn withdraw\|goal\|amount_raised" programs/rustfund/src/lib.rs
16: fund.goal = goal;
19: fund.amount_raised = 0;
50: fund.amount_raised += amount;
90: pub fn withdraw(ctx: Context<FundWithdraw>) -> Result<()> {
91: let amount = ctx.accounts.fund.amount_raised;
186: pub goal: u64,
189: pub amount_raised: u64,

withdraw() at line 90 reads amount_raised (line 91) and transfers it with no comparison to fund.goal. A creator with 2 SOL raised against a 5 SOL goal can call withdraw() immediately and drain all contributions.

Recommended Mitigation

Add a goal check at the top of withdraw() before any transfer. This enforces the crowdfunding invariant on-chain:

+ require!(
+ ctx.accounts.fund.amount_raised >= ctx.accounts.fund.goal,
+ ErrorCode::GoalNotMet
+ );
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge 18 days ago
Submission Judgement Published
Validated
Assigned finding tags:

[H-02] H-01. Creators Can Withdraw Funds Without Meeting Campaign Goals

# H-01. Creators Can Withdraw Funds Without Meeting Campaign Goals **Severity:** High\ **Category:** Fund Management / Economic Security Violation ## Description The `withdraw` function in the RustFund contract allows creators to prematurely withdraw funds without verifying if the campaign goal was successfully met. ## Vulnerability Details In the current RustFund implementation (`lib.rs`), the `withdraw` instruction lacks logic to verify that the campaign's `amount_raised` is equal to or greater than the `goal`. Consequently, creators can freely withdraw user-contributed funds even when fundraising objectives haven't been met, undermining the core economic guarantees of the platform. **Vulnerable Component:** - File: `lib.rs` - Function: `withdraw` - Struct: `Fund` ## Impact - Creators can prematurely drain user-contributed funds. - Contributors permanently lose the ability to receive refunds if the creator withdraws early. - Severely damages user trust and undermines the economic integrity of the RustFund platform. ## Proof of Concept (PoC) ```js // Create fund with 5 SOL goal await program.methods .fundCreate(FUND_NAME, "Test fund", new anchor.BN(5 * LAMPORTS_PER_SOL)) .accounts({ fund, creator: creator.publicKey, systemProgram: SystemProgram.programId, }) .signers([creator]) .rpc(); // Contribute only 2 SOL (below goal) await program.methods .contribute(new anchor.BN(2 * LAMPORTS_PER_SOL)) .accounts({ fund, contributor: contributor.publicKey, contribution, systemProgram: SystemProgram.programId, }) .signers([contributor]) .rpc(); // Set deadline to past await program.methods .setDeadline(new anchor.BN(Math.floor(Date.now() / 1000) - 86400)) .accounts({ fund, creator: creator.publicKey }) .signers([creator]) .rpc(); // Attempt withdrawal (should fail but succeeds) await program.methods .withdraw() .accounts({ fund, creator: creator.publicKey, systemProgram: SystemProgram.programId, }) .signers([creator]) .rpc(); /* OUTPUT: Fund goal: 5 SOL Contributed amount: 2 SOL Withdrawal succeeded despite not meeting goal Fund balance after withdrawal: 0.00089088 SOL (rent only) */ ``` ## Recommendations Add conditional logic to the `withdraw` function to ensure the campaign has reached its fundraising goal before allowing withdrawals: ```diff pub fn withdraw(ctx: Context<FundWithdraw>) -> Result<()> { let fund = &mut ctx.accounts.fund; + require!(fund.amount_raised >= fund.goal, ErrorCode::GoalNotMet); let amount = fund.amount_raised; **ctx.accounts.fund.to_account_info().try_borrow_mut_lamports()? = ctx.accounts.fund.to_account_info().lamports() .checked_sub(amount) .ok_or(ProgramError::InsufficientFunds)?; **ctx.accounts.creator.to_account_info().try_borrow_mut_lamports()? = ctx.accounts.creator.to_account_info().lamports() .checked_add(amount) .ok_or(ErrorCode::CalculationOverflow)?; Ok(()) } ``` Also define the new error clearly: ```diff #[error_code] pub enum ErrorCode { // existing errors... + #[msg("Campaign goal not met")] + GoalNotMet, } ```

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