How I Identify Repeat Fraudsters Across Accounts

In my experience managing digital fraud prevention, one of the most valuable tools I’ve used is the ability to identify repeat fraudsters across accounts. Early in my career, I relied mostly on email addresses and IP checks, but I quickly realized that sophisticated fraudsters could easily rotate emails, use VPNs, or spoof IPs. Device-level analysis became a game-changer, allowing me to detect patterns that link multiple accounts to the same underlying user.

I recall a situation with a growing e-commerce client who kept losing money to “friendly fraud,” where customers placed orders and then disputed charges claiming they never received the products. Initially, it seemed like isolated cases. However, after profiling devices associated with the accounts, we discovered several repeat offenders using the same mobile devices, even though they registered under different emails and shipping addresses. By flagging these devices, we were able to block fraudulent orders before they were processed, saving the client thousands of dollars in losses over a few months.

Another case involved a fintech startup that faced repeated sign-up bonuses being claimed fraudulently. A small group of users would create multiple accounts to cash in on referral programs. What stood out during our investigation was that the fraudsters often used the same device hardware but in different virtual environments. Device fingerprinting revealed matching characteristics like browser configurations, screen resolutions, and installed fonts. Once we implemented device-level linking, the fraudulent activity dropped dramatically, and legitimate customers experienced no disruption.

I’ve also noticed that many organizations make the mistake of relying solely on static identifiers, like email or phone numbers. One client, a subscription service, was repeatedly seeing new accounts linked to fraudulent credit cards. By focusing on device fingerprints, we were able to connect accounts that would otherwise appear unrelated. For instance, one customer kept reappearing with different usernames, but the device fingerprint—capturing subtle system and browser attributes—remained consistent. This allowed the company to preemptively block attempts and strengthen their verification process without inconveniencing real users.

From my perspective, understanding how to track repeat fraudsters across accounts is essential for protecting revenue and maintaining trust. Device-based profiling adds a layer of visibility that traditional identifiers often miss. It allows fraud teams to act proactively rather than reactively, identifying repeat offenders before significant damage occurs.

In my decade of experience, the organizations that successfully minimize fraud aren’t necessarily the ones with the strictest rules—they are the ones that leverage detailed device insights to distinguish legitimate users from repeat offenders. When implemented thoughtfully, device fingerprinting becomes an essential component of any fraud prevention strategy, helping businesses protect themselves while keeping genuine customers happy.