The U.S. affiliate marketing industry is entering a new phase of scale.
It is crossing the $10 billion mark for the first time, up from $9.1 billion in 2023, and projected to reach $14.8 billion by 2028. With giants like Amazon, Walmart, and Target running large, complex affiliate programs, the stakes have never been higher.
But as the channel grows, so does the race to claim commissions (sometimes wrongfully) which can also look like this – imagine a shopper comes directly to your website, ready to buy yet somehow, a third-party partner ends up taking credit for that sale. Many brands are already trying to tackle it, but the growing sophistication of the tactic makes it increasingly difficult to control.
In this blog, we dive into a sophisticated tactic known as cookie hijacking where affiliate cookies are secretly inserted into a user’s browser to claim credit for organic traffic, ultimately stealing conversions that rightfully belong to the brand.
Behind the Scenes of Cookie Hijacking: 3 Tactics You Might Be Missing
Here are three common ways affiliates cause cookie stealing to hijack organic traffic:
Extensions Injecting Cookie
Affiliates driving sales by influencing real customers is ideal but them stealing is not. One common way an affiliate program experiences this issue is through cookie hijacking. While analyzing a leading global e-commerce platform, we found that many users were directly visiting the site to make purchases. However, some had browser extensions installed (like coupon or deal tools) that silently triggered affiliate links in the background, without any click or user consent. As a result, when the purchase was completed, the system attributed it to an affiliate. Since most tracking follows a “last click wins” model, the affiliate whose cookie was dropped last received the credit, despite having no real influence on the sale.
Auto-redirect with Affiliate Tag
Another way of cookie hijacking that we noticed in the same brand’s use case was, the page as when users were redirected to brand’s website. If a user is browsing normally and visits a random page (this could be a shady site, popup, or even hidden script). The page quickly redirected them to brand’s site and in a split-second redirect, an affiliate cookie is dropped silently. When that user makes purchase, the credit is given to the affiliate as system sees the cookie.
Forced cookie from an external site
A user visits a completely unrelated website, not your brand’s. In the background, that site quietly drops an affiliate cookie without the user clicking anything or showing any intent. Sometimes, the user is even redirected to your website, making it look like a normal visit. Later, when they make a purchase, the affiliate gets credit, simply because their cookie was already placed earlier.
How Can You Safeguard Your Brand From Cookie Hijacking
Cookie manipulation is a growing risk for U.S. brands, especially those running large-scale affiliate programs. As partner ecosystems expand, having clearer visibility becomes essential to avoid affiliate fraud and protect genuine performance.
Legacy, surface-level tools can highlight obvious issues, but the real question is whether they can keep up with increasingly sophisticated fraud tactics. In most cases, they fall short. And for U.S. brands running high-stakes affiliate programs , uncertainty isn’t something they can afford.
With a more advanced, third-party approach like mFilterIt’s, renowned brand are already bringing more transparency to their affiliate marketing programs. Here’s how it empowers brands-
- Launch instantly, stay in control – No integrations needed, just immediate visibility into your affiliate ecosystem
- Gain complete transparency – Always-on scanning ensures you see every leakage, not just the obvious ones
- Expand your risk coverage – Protect your brand from both known partners and unknown bad actors
- Make decisions with confidence – Accurate, low-noise insights you can actually act on
- Hold the right partners accountable – Clear attribution helps you take precise, effective action
- Understand your true customer journey – See exactly how users reach and convert on your platform
- Protect revenue in real time – Identify and stop fraud before it impacts your bottom line
Conclusion
The key to a smooth affiliate program is visibility to understand real user journeys and know where attribution is coming from. Brands that focus on transparency and proactive monitoring through holistic ad fraud solution can prevent revenue leakage and build stronger, more reliable affiliate programs.
FAQs
What is cookie theft?
Cookie theft is when someone steals a user’s cookie or places their own cookie in the user’s browser to wrongly take credit for a purchase they didn’t influence at the first place.
How to prevent cookie hijacking?
- Monitor affiliate traffic and user journeys closely
- Block suspicious extensions, redirects, and unknown sources
- Validate partners and enforce strict program rules
- Use advanced tracking/monitoring tools for better visibility
Why is cookie hijacking difficult to identify?
Cookie hijacking is difficult to identify because it often happens silently in the background. Since the user still completes a genuine purchase, the fraud appears legitimate in standard attribution systems, making it harder for legacy tools to flag.
