Web Security

Web Skimming

In web development and particularly in web security, cybersecurity threats loom large, especially in online transactions. One such emergent threat is web skimming, which targets financial transactions conducted on the Internet.

What is Web Skimming?

Web skimming, also known as e-skimming or Magecart attacks, is about cybercriminals injecting malicious code into a website, typically on payment pages. This code is designed to capture sensitive information that users enter during the checkout process, such as credit card details, personal identification numbers, and other personal data. The stolen data is then transmitted to servers controlled by the attackers, who may use it for fraudulent transactions or sell it on the dark web.

How Does it Work: Mechanisms of Web Skimming

  • Target Identification: Attackers begin identifying vulnerable websites, often focusing on e-commerce sites due to their high traffic and volume of payment transactions. They look for outdated systems, unpatched software, or poorly secured third-party services integrated into the target website.

  • Gaining Access: The entry point for web skimming can vary. Attackers may use known vulnerabilities in web platforms like content management systems (CMS) or e-commerce platforms that haven’t been updated or patched. Many websites use external plugins for various functionalities, such as ads, analytics, or payment gateways, and here attackers might infiltrate these third-party services, especially if they're not securely configured. Sometimes, the direct attack vector can be through phishing campaigns targeting employees of the company, and successfully deceiving an employee can provide attackers with the necessary credentials to access web application infrastructures.

  • Injection of Skimming Code: Once access is obtained, attackers inject malicious JavaScript code into the website’s pages. This script is often:

    • Highly Obfuscated: To avoid detection, the malicious code is typically obfuscated, making it look benign or like legitimate analytics or payment scripts.

    • Dynamically Loaded: The malicious scripts may only activate under certain conditions to avoid raising suspicions, such as only executing when the checkout page is accessed or when certain form fields are interacted with.

  • Data Capture: The skimming code is designed to listen for specific user actions, like filling out a payment form. When a user enters their payment information, the script captures this data in real time. The script can capture everything typed into a form field, even if the user does not submit the form.

  • Exfiltration: The stolen data is then packaged and sent to a server controlled by the attackers. This transmission is often disguised to look like legitimate network traffic or is encrypted to bypass security measures that monitor for data leaks.

  • Persistence and Spread: In more advanced skimming operations, the code might include mechanisms to maintain persistence on the infected site or to spread laterally to other parts of the web infrastructure, which could entail creating backdoors or compromising more accounts.

Web Skimming: Preventative Measures and Best Practices

Web skimming represents a dangerous threat in the web security landscape, primarily due to its stealthy nature and potentially devastating impact. Awareness and proactive measures are key in combating these attacks. As cybercriminals continually refine their methods, the need for robust cybersecurity strategies becomes more critical. Here’s a list of best practices to adopt to prevent web skimming: 

  • Regular Security Audits: Conducting regular security assessments can help identify and fix vulnerabilities that could be exploited by skimmers.

  • Enhanced Monitoring: Implementing real-time monitoring tools to detect unusual script behaviors or unauthorized changes can alert administrators to potential breaches.

  • Using Subresource Integrity: This feature for browsers aids to verify that resources fetched from servers are delivered without unexpected manipulation; it always uses cryptographic hashes to check the integrity of each script.

  • Content Security Policy (CSP): Setting up a CSP can restrict the sources from which scripts can be loaded, significantly reducing the risk of malicious script injection.

  • Third-Party Management: Since third-party services are a common vector for attacks, it’s really, really vital to audit and monitor all third-party components integrated into a website.

Impact of Web Skimming

The implications of web skimming are severe. For individuals, it leads to financial loss and potential identity theft. For businesses, the consequences extend to damaged reputation, loss of customer trust, and potentially significant financial and legal repercussions. Businesses must stay vigilant, upgrade their security postures regularly, and ensure compliance with the latest security standards to protect themselves and their customers from this pervasive threat.

In addition to technical safeguards, it’s important to educate stakeholders about the risks and indicators of web skimming, including training employees, especially those involved in web development and maintenance, to recognize the signs of a potential breach and understand the best practices for securing web applications.

Collaboration among businesses, cybersecurity experts, and law enforcement can lead to better security protocols and quicker responses to threats. Sharing information about emerging threats, attack vectors, and effective countermeasures can help the entire industry stay one step ahead of cybercriminals.

Protect your Website with Jscrambler: Third-party Application Security

The Jscrambler Client-Side Protection Platform safeguards first-party JavaScript through state-of-the-art obfuscation and exclusive runtime protection.

Its fine-grained JavaScript behavioral analysis also mitigates threats and risks posed by third-party tags all while ensuring compliance with the new PCI DSS v4.0 standard. With Jscrambler, businesses adopt a unified, future-proof client-side security policy all while achieving compliance with emerging security standards.

Trusted by digital leaders from several industries, including financial, healthcare, and entertainment, Jscrambler gives businesses the freedom to innovate securely.

How Jcrambler can help you

Gain visibility and control of all code running on the client-side.

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