SMS Pumping Fraud: What it is, How to Detect it, and How to Prevent it

SMS pumping fraud is a sophisticated scam where attackers exploit phone verification systems to generate large volumes of SMS traffic to premium-rate numbers they control, leading to substantial financial losses for businesses. This type of fraud, also known as Artificially Inflated Traffic (AIT), is a subset of International Revenue Share Fraud (IRSF) and specifically targets OTP and verification endpoints. Fraudsters collaborate with unethical mobile carriers or manipulate SMS routes to create fake traffic, with businesses unknowingly shouldering the costs. The scam is particularly effective because OTP systems are inherently vulnerable due to their open nature, allowing bots to trigger SMS sends without authentication requirements. Detecting SMS pumping involves monitoring unusual spikes in OTP requests, sequential phone number patterns, and traffic from unexpected geographies. Prevention strategies include implementing adaptive rate limiting, pre-send phone number classification, and geographic restrictions, as well as leveraging advanced fraud detection tools like Prelude's Watch API to block high-risk requests before they incur costs. Despite the potential for significant financial damage and operational disruptions, proactive fraud management and real-time detection can mitigate the risks posed by SMS pumping fraud.