Front-End Attacks in Web3: Causes, Impact, and Lessons Learned

Massa Labs
4 min readOct 13, 2023

The rise of DeFi has ushered in a new era of innovation and financial freedom. However, this rapid growth has also attracted the attention of malicious actors looking to exploit vulnerabilities. While much focus has been placed on smart contract security, front-end attacks are emerging as a significant threat vector.

The Anatomy of Front-End Attacks

Understanding the various techniques attackers use to exploit front-end vulnerabilities is essential for both developers and users in Web3. From DNS hijacking to code injection, these methods pose significant risks that demand attention.

DNS Hijacking

Domain Name System (DNS) hijacking is a common method where attackers gain control over a domain’s DNS settings. By doing so, they can redirect traffic to a malicious server, effectively serving as a gateway for phishing or data theft. Balancer, a popular DeFi platform, fell victim to such an attack, leading to significant financial losses and eroding user trust.

Code Injection

Attackers can exploit vulnerabilities in the front-end code to inject malicious scripts. These scripts can manipulate smart contract interactions, leading to unauthorized transactions or data theft. Kyber Network’s front-end hack, which resulted in a loss of around $265,000, was a classic example of code injection. The attacker injected malicious code into Kyber Network’s Google Tag Manager, which supports the site’s Google Analytics, thereby gaining control over user funds.

Phishing Attacks

In phishing attacks, users are often tricked into interacting with a counterfeit version of the website. These fake platforms usually aim to collect sensitive information like passwords or private keys. Once obtained, this information can be used for unauthorized transactions or data theft across various platforms and services.

Cross-Site Scripting (XSS)

XSS attacks involve injecting malicious scripts into web pages viewed by other users. These scripts can steal information like login tokens or even execute unauthorized transactions on behalf of the user.

Man-in-the-Middle (MitM) Attacks

In MitM attacks, the attacker intercepts data being sent between the user and the server. This can be achieved by compromising public Wi-Fi or using rogue software to intercept data.

The Impact of Front-End Attacks

While immediate financial setbacks often grab headlines, the consequences of front-end attacks extend to data breaches and a loss of user trust, affecting the long-term health of platforms in Web3.

Financial Loss

The most immediate and obvious impact of a front-end attack is financial loss. For instance, Curve Finance was hacked twice, once leading to a loss of $52 million and another time causing a $575,000 loss. These attacks not only result in direct financial loss but also affect the platform’s native token value.

Data Breach

Personal and sensitive information, such as private keys and login credentials, can be stolen during these attacks. This data can be used for further attacks and sold on the dark web.

Loss of Trust

Perhaps the most long-lasting impact is the erosion of trust. Users are less likely to interact with platforms that have suffered from security breaches, affecting the platform’s long-term viability.

Lessons Learned and Preventive Measures

Adopting best practices and preventive measures can significantly mitigate the risks associated with front-end attacks. From proper validation of user inputs to implementing multi-factor authentication, these strategies offer added layers of security.

Better Validation

Front-end code must properly validate all user inputs to prevent injection attacks. This includes using prepared statements for database queries and employing output encoding when rendering user-generated content.

Multi-Factor Authentication (MFA)

Implementing MFA can add an extra layer of security, making it difficult for attackers to gain unauthorized access even if they manage to steal login credentials.

Regular Audits

Security audits, both internal and third-party, can help in the early detection of vulnerabilities. These audits should be comprehensive, covering both smart contracts and front-end code.

User Education

Educating users on how to spot phishing attempts and the importance of secure connections can significantly reduce the risk of falling victim to front-end attacks.

Real-Time Monitoring

Platforms should employ real-time monitoring tools that can quickly identify and mitigate attacks. Automated alerts can be set up for suspicious activities, allowing for immediate action.

Introducing Massa Station: A Solution for Front-End Security

As the Web3 space continues to grapple with front-end vulnerabilities, Massa Station offers one solution. Built on Massa’s layer 1 blockchain, Massa Station provides on-chain web hosting, ensuring the same level of decentralization and security for dApp frontends as for smart contract backends. By moving the front-end on-chain, Massa Station eliminates the risks associated with DNS hijacking, code injection, and other front-end attacks, making it a game-changer in fortifying Web3 security.

While smart contracts and blockchain technology offer robust back-end security, the front-end remains a vulnerable attack vector. Understanding the technicalities behind these attacks is crucial for both developers and users to take preventive measures. As the Web3 space evolves, it becomes imperative for platforms to continually update and fortify their security protocols, ensuring a safer and more secure ecosystem.



Massa Labs | Massa is a truly decentralized blockchain controlled by thousands of people. With our multithreaded technology, we’re set for mass adoption.