Ecomerce Threats

From live chat and analytics to review widgets and payment processors, modern eCommerce sites rely heavily on third-party tools. But what happens when one of those “trusted” scripts gets compromised?

Malicious third-party scripts are one of the most under-the-radar threats facing online stores today — and they can cause massive damage without ever touching your server.

What Are Third-Party Scripts?

A third-party script is any piece of JavaScript code your website loads from another source — typically via a <script> tag from an external URL.

Common examples:

• Google Analytics
• Facebook Pixel
• Hotjar, HubSpot, or other marketing tools
• Payment gateways (e.g. Stripe, PayPal integrations)
• Review or loyalty program widgets
• Chatbots or helpdesk tools

These scripts run inside your site and interact with your users — sometimes even collecting form data or influencing the checkout flow.

The Risk: What Can Go Wrong?

If a third-party script is compromised — either because their server is hacked or the code itself is intentionally malicious — it has free access to your page and your users.

That means attackers can:

• Inject keyloggers or card skimmers
• Steal form submissions
• Redirect users to phishing pages
• Load malware onto your visitors’ browsers
• Modify prices, content, or button behaviour
• Track users across other sites without consent (GDPR nightmare)

You may never know until a customer complains — and by then, it’s already too late.

Real-World Case

In 2018, Ticketmaster was breached through a third-party chatbot provider. Attackers injected a malicious script that skimmed payment info from thousands of customers.

Ticketmaster’s own infrastructure wasn’t breached — but they still paid the price.

This is supply chain compromise in action: attackers don’t need to hack you directly — they just need to exploit who you trust.

Why Third-Party Scripts Are So Dangerous

• They run with the same privileges as your own code
• They’re loaded in the user’s browser, not your server (so backend scans miss them)
• Most sites load dozens of third-party scripts — many not audited
• Even “reputable” tools can be vulnerable or bought by bad actors

How to Spot Malicious Scripts

Look out for:

• Unexpected requests to unfamiliar domains in developer tools
• Scripts loading from IP addresses instead of domain names
• Long or heavily obfuscated JavaScript files
• Scripts that load additional resources dynamically
• Tools you don’t remember installing (often legacy or inherited)

How to Protect Your Store

1. Use a Content Security Policy (CSP)

This limits what domains are allowed to load scripts, reducing the risk of unauthorised injections.

2. Audit all third-party services regularly

Know what you’re loading, why, and whether it’s still needed.

3. Use Subresource Integrity (SRI) where possible

It ensures that externally loaded scripts haven’t been tampered with.

4. Avoid inline scripts where possible

Inline scripts (especially eval or document.write) are easier for attackers to abuse.

5. Monitor your site continuously

Tools or your built-in browser CSP reporting can alert you to script changes in real time.

6. Be careful with “free” tools and plugins

If it’s free and collecting user data — it’s probably profiting off that data somehow.