As affiliate marketing grows as a cost-efficient channel, fraudsters are exploiting it with sophisticated schemes like cookie stuffing and last-click theft—draining budgets, distorting attribution, and eroding trust between brands and legitimate partners.
Affiliate marketing has become a key revenue driver for budget-conscious marketers, but fraudsters are exploiting influencer selling with increasingly sophisticated tactics.
The collaboration between marketers and their affiliate partners is key to ensuring brands are only paying for real results. Marketers, however, are unaware that they’re paying out to fraudsters instead of legitimate affiliates. With ad fraud projected to cost advertisers $71 billion in 2025, this is an epidemic marketers can’t afford to ignore.
Not only are budgets affected, but the brand’s reputation is impacted and legitimate affiliate partners are discredited.
The Growing Affiliate Threat
Affiliate fraud can occur when websites or individuals, who are paid a commission for the promotion of a product or service, use fraudulent tactics to generate revenue for personal gain.
While it began as fake purchases or click farms, fraudsters can now carry out more sophisticated attacks.
Here are some of the modern tactics they are using to manipulate branded campaigns and marketers:
Cookie Stuffing: This tactic involves fraudulent affiliates dropping third-party cookies into an unknowing visitor’s web browser to trick websites into thinking the affiliate has sent them the traffic. The false information in this cookie then deceives marketers into misattributing engagement that was sent by a fraudster, not a legitimate partner. Cookie stuffing impacts 5-10% of affiliate marketing transactions, significantly distorting attribution.
URL Hijacking: Fraudsters will register a domain name incredibly similar to a brand’s, targeted at users who have incorrectly typed the brand’s name into their browser. These users will be led to the fraudster’s alternate site instead of the one they intended to visit. The site then automatically redirects the user to the correct site with affiliate links, allowing the fraudsters to claim attribution.
Last-Click Theft: This is a sophisticated tactic in which fraudsters disguise themselves as a legitimate browser extension. From there, the fraudster will inject a click seconds before a purchase is finalized to be fraudulently rewarded for the referral. Users can also be invited to click on a discount code and copy it. When used, the fraudulent affiliate can then generate a hidden referral click in the background to steal attribution.
Ensuring Trust and Transparency
To stop unknowingly rewarding fraudsters for the work being done by real partners, marketers need to take steps to identify fraudulent tactics and stop them. Regularly auditing traffic gives marketers the chance to identify fraud before it has the chance to directly impact budgets.
In many cases, marketers are paying commission to affiliate partners when the end user actually ended up on their website organically or via another paid channel. The affiliate then uses underhanded tactics to claim that user’s conversion.
An influx of traffic from suspicious sources or locations is a potential indicator that fraudsters are attempting to interfere with a campaign. Marketers should also be on the lookout for certain affiliates being paid for excessively high commissions that don’t have the evidence to substantiate their contribution.
Marketers should use a comprehensive vetting process for potential affiliate partners. A basic step would be to ensure their email address matches their website’s URL to verify their identity. Reviewing affiliate platforms before partnering with them is also crucial to determine if they’re a legitimate candidate.
Securing Future Growth
Affiliate marketing has opened up new avenues for marketers to reach their audiences without breaking the bank. However, the system is inherently vulnerable to increasingly manipulative and damaging fraud tactics, and they’re happening without marketers even being aware they’ve been targeted.
Brands need to constantly keep ahead of evolving threat tactics. By using proven strategies to audit traffic, verify engagement and defend ad budgets, marketers can ensure every dollar works toward genuine acquisition and revenue growth.