When users trade OTC, scammers claim that they need to test the security of their wallets before trading and induce users to click a link or scan a QR code to enter a third-party website to conduct a "wallet security test". 

Actually they are trying to steal users' token approval which will allow the scammer to transfer USDT out of users’ wallets without their consent.

PSA: Read this blog on how to spot token approval scam and stay alert! Do not trust the so-called wallet security testing software or websites.