Proxy Washing

Overview

Proxy washing is an evasive technique used by fraudsters to mask their digital footprint. By rapidly rotating through a large pool of proxy IP addresses, they can make their malicious activities appear as if they are coming from many different, unrelated users. This method is a significant challenge for traditional fraud detection systems that rely heavily on IP address reputation and rate limiting.

How Proxy Washing Works

At its core, proxy washing involves routing internet traffic through a series of proxy servers. A fraudster, or a bot they control, will make a request from one IP address, then for the next request, switch to a completely different one. This cycle can repeat hundreds or thousands of times in a single fraudulent session. These proxies can range from datacenter IPs, which are easier to detect, to more sophisticated residential or mobile proxies, which belong to real users whose devices have been unknowingly co-opted. This rapid switching makes it incredibly difficult to link a series of malicious actions to a single perpetrator based on IP alone.

Why It's a Threat to Your Business

Proxy washing is a practical tool used to enable various forms of online fraud and abuse. Here's how it impacts businesses:

• Credential Stuffing & Account Takeover (ATO): Attackers use proxy washing to attempt thousands of logins with stolen credentials. By rotating IPs for each attempt, they bypass rules that would typically block or flag a single IP after a few failed logins.
• New Account Fraud: Fraudsters create thousands of synthetic or fake accounts for activities like promotion abuse, spamming, or manipulating social platforms. Proxy washing makes these accounts appear to originate from a diverse and legitimate user base.
• Carding and Payment Fraud: Criminals test the validity of stolen credit card numbers by making small purchases. They use washed proxies to distribute these attempts across countless IP addresses, evading velocity checks that would normally detect this pattern.
• Web Scraping & Content Theft: Malicious bots hide behind washed proxies to steal pricing data, proprietary content, or product inventory information without being detected and blocked.

Detecting and Preventing Proxy Washing

Combating proxy washing requires a multi-layered approach that looks beyond the IP address. At Greip, we focus on identifying the actor, not just their temporary address. Effective strategies include:

Advanced IP Intelligence: Go beyond simple blacklists to identify the type* of IP address being used. Is it a known datacenter, a residential proxy, a public VPN, or a Tor exit node? Understanding the context of the IP is key.

• Device Fingerprinting: This is a critical layer of defense. Even when an IP address changes every second, the underlying device—with its unique combination of operating system, browser, and hardware specifications—often remains the same. A persistent device fingerprint can link a thousand washed IPs back to a single fraudulent user.
• Behavioral Analytics: Sophisticated systems can analyze user behavior in real-time. A human user doesn't typically attempt 50 logins in 10 seconds or fill out a form in milliseconds. By monitoring for inhuman speed, session inconsistencies, and other behavioral anomalies, you can spot bots, regardless of their IP.
• Link Analysis: Connecting the dots between seemingly unrelated data points is crucial. By analyzing the relationships between device fingerprints, user agents, email addresses, and other session data, you can uncover hidden patterns that reveal a coordinated attack campaign.

Conclusion

Proxy washing demonstrates that relying on IP addresses as a primary defense mechanism is no longer a viable strategy. Fraudsters continuously adapt their methods to bypass simplistic security rules. To effectively protect your platform from abuse and financial loss, you need a robust fraud prevention solution that analyzes a wide array of signals. By combining device fingerprinting, behavioral analysis, and advanced IP intelligence, businesses can look past the mask of rotating proxies to identify and block the malicious actors hiding behind them.