Entangle Trillion DexWrapper accepts `amountOutMin = 0` — MEV sandwich

Source & credit. Reproduction of a public audit finding curated by AuditVault — the original finding: 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks. Standalone Foundry PoC and full write-up: 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks_exp in the evm-hack-registry mirror.

Vulnerability classes: vuln/defi/mev-sandwich · vuln/defi/missing-slippage-bound

Reproduction: the test deploys the REAL audited RamsesWrapper (an Entangle Trillion DexWrapper, verified on-chain at 0xc33b58b341046b4ddbcf0f85435bf361ee4b268c on Arbitrum) and executes the sandwich the missing amountOutMin bound enables. A protocol routes a swap through RamsesWrapper.swapAny(..., amountOutMin = 0, ...); an attacker front-runs and back-runs it against a real constant-product pool, extracting a concrete profit.

Root cause#

The Entangle Trillion DeFi layer swaps through thin DexWrapper contracts (the Halborn report names UniswapHandler; the on-chain-verified sibling used here is RamsesWrapper). The wrapper performs the swap with a caller-supplied amountOutMin and enforces no minimum of its own:

// RamsesWrapper.swapAny  (real, unmodified)
function swapAny(address router, uint256 amountIn, uint256 amountOutMin, route[] calldata routes)
    external payable returns (uint256[] memory amounts)
{
    return IRamsesRouter(router).swapExactTokensForTokens(
        amountIn, amountOutMin, routes, msg.sender, block.timestamp + 1000   // @> amountOutMin passed straight through
    );
}

Entangle's calling code passes amountOutMin = 0, so the protocol's trade has no slippage bound and executes at whatever price the pool is in when the transaction lands. Because the transaction is public in the mempool, an attacker can move the pool before it executes (front-run), let the protocol trade at the manipulated price, then restore the pool (back-run) — a classic sandwich.

The real vulnerable contract is vendored verbatim (topologically re-ordered, imports inlined) at src/Entangle51371.sol (RamsesWrapper). The audited GitHub repository Entangle-Protocol/entangle-lsd-protocol has since been taken private/deleted; the exact deployed source is recovered from the Arbitrum verified-source mirror.

Reproduction#

The fixture deploys a real constant-product AMM venue (x*y=k, 0.3 % fee) seeded 1,000,000 / 1,000,000 (true price 1:1), the real RamsesWrapper, and a Victim protocol that routes a 50,000-token swap through swapAny(..., amountOutMin = 0, ...):

1. Front-run — the attacker swaps 300,000 B → A, pushing A's price up.
2. Victim — the protocol swaps 50,000 B → A through the real wrapper with no minimum. It receives 28,427 A instead of the un-sandwiched 47,482 A (a ~40 % / 19,055-A shortfall).
3. Back-run — the attacker sells the A back at the inflated price and ends with +19,180 B.

cd 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks_exp
../_shared/run-poc/run_poc.sh 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks_exp -vvvvv

Expected result: 1 passed. The assertions in test/51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks_exp.sol prove the attacker profits > 15,000 B and the victim receives materially less than the fair output.

Fix#

Require a non-zero amountOutMin derived from an on-chain quote (getAmountsOut) minus an acceptable slippage tolerance, and revert if the realized output is below it. (Halborn marked the finding Not Applicable because the DexWrapper code path was deprecated; the verified on-chain deployment still carries no internal bound.)

Sources#

• AuditVault finding #51371
• Halborn — Entangle Trillion audit
• Deployed verified source: RamsesWrapper @ 0xc33b58b341046b4ddbcf0f85435bf361ee4b268c (Arbitrum), mirrored in tintinweb/smart-contract-sanctuary-arbitrum

Sources & further analysis#

Reproductions & code

• Standalone PoC + full trace: 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks_exp (evm-hack-registry mirror).
• AuditVault finding: 51371-exploiting-zero-amountoutmin-in-dexwrappers-for-mev-attacks.
• Upstream DeFiHackLabs PoC directory: src/test.

Alerts & third-party analyses

• DeFiHackLabs incident explorer: search "Entangle Trillion DexWrapper accepts amountOutMin = 0".
• Web3Sec X hacked database: search.
• Rekt leaderboard: search.
• Solodit incident search: search.

These dashboards index community alerts tweets, post-mortems, and independent write-ups. Reach them through the protocol name above to cross-check this reproduction against other analyses.