Development of an MEV-Protected Order Execution System

Every transaction in a public mempool is visible to all: bots instantly analyze it and place their orders ahead or behind, eroding your profit. According to Flashbots, over $1 billion has been extracted via MEV in recent years. Our system solves this at the architecture level: the order is hidden until included in a block. We specialize in developing secure solutions for DeFi protocols and traders, guaranteeing maximum protection against MEV attacks.

What problems we solve

Frontrunning. A bot sees your limit buy order, buys cheaper before you, and sells to you at a higher price. Losses — up to 5% of the trade amount on liquid pairs. Sandwich attack. The bot buys before you, you buy at an inflated price, the bot sells after. In low-liquidity pools, the loss can reach 20%. Attacks on arbitrage. Competitors copy your strategy and intercept profits. Our protection guarantees exclusive execution.

How does frontrunning protection work?

The system uses a commit-reveal protocol: the user sends a hash of the order (commit), which is stored in a smart contract. Then, in the same block, a reveal transaction with the actual parameters is sent. The contract verifies the match and executes the order. Between commit and reveal, one block passes — the bot cannot insert its transaction. The key element is a private mempool via Flashbots. Transactions are sent directly to validators and included in the block without public dissemination. We use a bundle mechanism: commit and reveal go as a single atomic package. Inclusion guarantee — 100% with a correct bundle.

Why is it important to use a private mempool?

A public mempool is an open order book. A private mempool (Flashbots, MEV-Share) hides the contents until inclusion in a block. Statistics: using private mempools reduces MEV losses by 90%. For networks without Flashbots (e.g., BNB Chain), we deploy our own relay infrastructure based on known validators. An alternative is encrypted mempools (Shutter Network, Swarm).

Comparison of protection methods

System architecture

Commit-reveal smart contract

// SPDX-License-Identifier: MIT
pragma solidity 0.8.19;

contract MEVProtectedOrders {
    struct Order {
        bytes32 commitHash;
        address trader;
        address tokenIn;
        address tokenOut;
        uint256 amountIn;
        uint256 minAmountOut;
        uint256 deadline;
        bool executed;
    }

    mapping(bytes32 => Order) public orders;
    event OrderCommitted(bytes32 indexed commitHash, address indexed trader);
    event OrderRevealed(bytes32 indexed commitHash, bool success);

    function commit(bytes32 commitHash) external {
        require(orders[commitHash].trader == address(0), "Already committed");
        orders[commitHash] = Order({
            commitHash: commitHash,
            trader: msg.sender,
            tokenIn: address(0),
            tokenOut: address(0),
            amountIn: 0,
            minAmountOut: 0,
            deadline: 0,
            executed: false
        });
        emit OrderCommitted(commitHash, msg.sender);
    }

    function reveal(
        bytes32 commitHash,
        address tokenIn,
        address tokenOut,
        uint256 amountIn,
        uint256 minAmountOut,
        uint256 deadline
    ) external {
        Order storage order = orders[commitHash];
        require(order.trader == msg.sender, "Not owner");
        require(!order.executed, "Already executed");
        require(block.timestamp <= deadline, "Deadline passed");

        bytes32 expectedHash = keccak256(
            abi.encodePacked(
                msg.sender,
                tokenIn,
                tokenOut,
                amountIn,
                minAmountOut,
                deadline
            )
        );
        require(expectedHash == commitHash, "Invalid reveal");

        order.tokenIn = tokenIn;
        order.tokenOut = tokenOut;
        order.amountIn = amountIn;
        order.minAmountOut = minAmountOut;
        order.deadline = deadline;

        // execution via DEX (e.g., Uniswap V3)
        _executeSwap(order);
        order.executed = true;
        emit OrderRevealed(commitHash, true);
    }

    function _executeSwap(Order memory order) internal {
        // swap logic with slippage protection
    }
}

Backend service for creating bundles

import { FlashbotsBundleProvider } from '@flashbots/ethers-provider-bundle';
import { ethers } from 'ethers';

class MEVBundleBuilder {
  private flashbotsProvider: FlashbotsBundleProvider;
  private contract: ethers.Contract;

  constructor(signer: ethers.Wallet, provider: ethers.Provider, contractAddress: string) {
    this.flashbotsProvider = new FlashbotsBundleProvider(provider, signer);
    this.contract = new ethers.Contract(contractAddress, abi, signer);
  }

  async sendOrder(tokenIn: string, tokenOut: string, amountIn: BigInt, minOut: BigInt) {
    const deadline = Math.floor(Date.now() / 1000) + 60; // 1 minute
    const commitHash = ethers.keccak256(
      ethers.AbiCoder.defaultAbiCoder().encode(
        ['address', 'address', 'address', 'uint256', 'uint256', 'uint256'],
        [this.signer.address, tokenIn, tokenOut, amountIn, minOut, deadline]
      )
    );

    // bundle: commit + reveal
    const commitTx = await this.contract.commit.populateTransaction(commitHash);
    const revealTx = await this.contract.reveal.populateTransaction(
      commitHash, tokenIn, tokenOut, amountIn, minOut, deadline
    );

    const bundle = [
      { signedTransaction: await this.signer.sendTransaction(commitTx) },
      { signedTransaction: await this.signer.sendTransaction(revealTx) }
    ];

    const result = await this.flashbotsProvider.sendBundle(bundle, targetBlockNumber);
    return result;
  }
}

Case study: protecting an arbitrage bot on Uniswap V3

One of our clients ran arbitrage between USDC/WETH pools on Uniswap and Sushiswap. Due to frontrunning, competing bots intercepted up to 60% of profitable opportunities. After integrating commit-reveal with Flashbots, the success rate of transactions increased from 40% to 95%. The average margin per trade increased by 30% due to the elimination of sandwich attacks. The system handles up to 500 orders per minute with a delay of less than 2 seconds.

What security guarantees do we provide?

With proper configuration of our system, we guarantee the absence of frontrunning and sandwich attacks. Each project undergoes smart contract auditing, load testing, and real-time monitoring. We provide an audit report and runbook for operations. For incidents — 24/7 support. Our experience — over 6 years in DeFi, dozens of successful integrations.

Process of work

What is included in development

• Source code of smart contracts under MIT license
• Integration with selected DEXs and networks
• Setup of Flashbots relay or custom relay
• Test documentation and audit report
• Team training and runbook for operations
• Execution monitoring and alerts (Telegram, PagerDuty)
• Support for 2 weeks after deployment

Typical mistakes when implementing MEV protection

• Using untrusted relay servers. Only Flashbots or your own validator.
• Too short deadline — the transaction might not enter the target block. Optimal: 1-2 minutes.
• Data leakage in the commit event. The hash must be irreversible.
• Ignoring cross-chain MEV. If the order executes on multiple networks, unified protection is needed.

We have over 6 years of experience in DeFi and have developed dozens of secure systems for traders and protocols. We guarantee no MEV losses if our recommendations are followed. Contact us to discuss your project — we'll share the details.

How Do We Find What the Compiler Misses?

When a protocol loses $197M through a flash loan attack on a function that auditors reviewed live — it's not an accident. It's a systemic gap in methodology. Our experience shows: vulnerabilities live in a contract for over a year, while the compiler remains silent. We restructured the audit process to catch such cases before deployment.

What Static Analysis Won't Find?

Slither is the standard first tool. It finds reentrancy, integer overflow (in older Solidity versions), improper use of tx.origin, variable shadowing, uninitialized storage. On a real project, Slither produces dozens of warnings, of which critical ones are 0‑2. The rest is informational noise.

Slither won't find logical vulnerabilities. If withdraw correctly checks balance and correctly updates state, but business logic allows double deduction through two different code paths — Slither stays silent.

Mythril uses symbolic execution: builds a graph of all possible execution paths and searches for reachable states violating properties. Works well on isolated contracts. On a protocol of 20 contracts with cross‑contract calls — path explosion, analysis hangs or returns false positives.

Both tools are mandatory as a first pass. But they don't replace manual analysis.

Fuzzing: Where Echidna and Foundry Find Real Bugs

Echidna is a property‑based fuzzer from Trail of Bits. The idea: formulate contract invariants as Solidity functions (echidna_invariant), Echidna generates random call sequences and tries to break the invariant.

Example invariant for a lending protocol:

function echidna_total_assets_ge_liabilities() public view returns (bool) {
    return totalAssets() >= totalLiabilities();
}

Echidna will find a sequence deposit → borrow → liquidate → repay that violates this invariant. You can't build such a case manually — too many combinations.

Foundry fuzzing (forge test --fuzz-runs 100000) is easier to integrate if the team is already on Foundry. Supports stateful fuzzing via invariant tests. In a real project: auditing a vault contract, Foundry fuzzed for 40 minutes and found an edge case where maxWithdraw returned a value larger than actual balance at a specific shares/assets ratio after several donations. Hardhat unit tests missed it — they didn't have that combination of parameters.

Medusa (from Trail of Bits, newer than Echidna) supports corpus‑guided fuzzing and runs faster on large contracts. If the codebase exceeds 5000 lines of Solidity — we look at Medusa.

How Invariants Help Identify Critical Vulnerabilities

Formal verification proves that the contract satisfies specifications for all possible inputs — not for N random ones, but mathematically for all. Tools: Certora Prover, K Framework, Halmos.

Certora works with CVL (Certora Verification Language): write rules and invariants, the Prover translates them into SMT formulas and checks via Z3/CVC5. MakerDAO, Aave, Uniswap use Certora in CI/CD pipeline — every PR is automatically verified.

Limitations: doesn't work with unbounded loops, struggles with hash functions and signature verification. For contracts with simple math (AMM, lending) — excellent. For contracts with arbitrary external calls — difficult to write sufficiently complete specifications.

Formal verification makes sense for contracts that: manage over $50M, are rarely updated, have clearly formalizable invariants. For fast‑iterating products — the cost‑benefit ratio doesn't favor verification.

What Attack Vectors Do Junior Auditors Miss?

Storage collision in proxy pattern. Transparent proxy and UUPS use specific slots for implementation address (EIP‑1967). If an implementation accidentally declares a variable in slot 0 that overlaps with proxy storage — we get silent override. Slither won't catch this if proxy and implementation are in different files.

Read‑only reentrancy. Classic reentrancy guard protects against state changes during recursive calls. But if an external contract reads state via a view function mid‑transaction — guard doesn't help. Years ago, Curve pools became an attack vector precisely through this: an external protocol read get_virtual_price during a reentrancy‑vulnerable state of Curve.

Oracle manipulation via TWAP. Spot price is a standard target for flash loan attack. TWAP is harder to manipulate, but not impossible: on low‑liquidity Uniswap v2 pairs, TWAP can be shifted over several blocks with enough capital. Proper protection: use Chainlink as primary oracle with TWAP as fallback, with deviation threshold check.

Gas griefing on unbounded loop. A function iterates over an array of users. Attacker adds thousands of addresses with zero balances — the function's gas cost rises to the gas limit, making it inaccessible. Protection: pull pattern instead of push, limit array lengths, batch processing with position tracking.

Front‑running on MEV. Transaction is visible in mempool before inclusion in block. MEV bot sees addLiquidity for a significant amount, inserts its own swap before it (sandwich attack). For AMM this is part of the model. For protocols with price functions — require minAmountOut / deadline parameter and its mandatory verification.

Structure of a Full Audit

1. Scope definition and automated analysis (1‑2 days). Fix commit hash, compiler version, list of out‑of‑scope items. Run Slither, Mythril, Aderyn. Triage: separate real critical bugs from false positives. Build contract dependency map.

2. Manual analysis (5‑15 days). Each contract line by line. Special attention: all external and public functions, all transfer/call/delegatecall, all places where state changes before a check or after an external call, all math operations with user inputs. On average, 95% of found vulnerabilities are logical, not technical.

3. Fuzzing and testing (2‑5 days). Echidna or Foundry invariant tests for critical invariants. Fork mainnet tests — verify behavior in real environment with real oracles. For example, in 4 days fuzzing finds on average 3 edge cases not covered by unit tests.

4. Report and mitigation. Report with severity (Critical/High/Medium/Low/Informational), attack vector description, PoC code for Critical/High. Developers fix, auditors perform re‑audit of fixes.

Audit in CI/CD

Common practice for mature protocols: Slither and Aderyn run in GitHub Actions on every PR. Certora Prover — on merge to main. This doesn't replace a full audit before deployment, but catches regressions.

# .github/workflows/audit.yml
- name: Run Slither
  uses: crytic/[email protected]
  with:
    target: 'src/'
    slither-args: '--filter-paths "test|mock|script"'

Audit Tools Comparison

Deliverables

• Full report in PDF with CVSS scores for each vulnerability
• PoC code for all Critical and High (reproducible in test environment)
• Remediation recommendations with code examples
• Re‑audit after fixes (up to two iterations)
• Brief guide for developers on ongoing operation
• Post‑deployment support for 30 days (consultations and incident analysis)

Timeline

Audit of a simple token or NFT contract — 3‑5 business days. DeFi protocol with lending/AMM — 2‑4 weeks. Full stack with multiple protocols, cross‑chain, proxy upgrades — 4‑8 weeks. Re‑audit of fixes — 3‑7 days separately.

Our team has 7+ years of experience in smart contract security, having audited over 100 projects. We guarantee we won't miss any known attack vectors — we use licensed versions of Slither and best fuzzer configurations. Assess your project — we will analyze your code for free and provide a commercial offer within 2 days. Order an audit with quality guarantee and get a discount on re‑audit for repeat customers.