Microsoft Dismantles Yam Store After 1 Billion Phishing Messages Hit 75,000 Organizations
Updated
Updated · Computerworld · Oct 15
Microsoft Dismantles Yam Store After 1 Billion Phishing Messages Hit 75,000 Organizations
3 articles · Updated · Computerworld · Oct 15
Summary
A nearly year-long Microsoft-led probe shut down Yam Store, a phishing-as-a-service marketplace tied to more than 1 billion malicious messages, including over 750 million aimed at Microsoft customers.
Japan’s National Police Agency triggered the investigation in late 2025 with reports of scam waves, and Microsoft said AI tools helped link accounts, websites and infrastructure across a broader Chinese-language criminal network.
Yam Store sold ready-made phishing kits, fraudulent Microsoft and Google accounts, and expired-domain scams; investigators identified three major kits and more than 2,300 impersonation templates spanning 150-plus countries.
Microsoft said the operation generated tens of millions of dollars and lowered the barrier for less-skilled criminals, while warning organizations to strengthen defenses with passkeys, MFA, conditional access and least-privilege controls.