MuMaYi Android Platform Breach: 128K Accounts Exposed

HEROIC's DarkHive intelligence system uncovered the MuMaYi data breach, exposing 127,574 records. The breach occured in May 2011 and affected users of MuMaYi, a China-based Android app platform at mumayi.cn. Compromised data included email addresses, usernames, IP addresses, birthdates, and MD5-hashed passwords.

Why This Is Dangerous

MD5 password hashes from 2011 are crackable with modern GPU arrays in hours or less. Combined with birthdates, attackers can answer common security questions and bypass account recovery processes on banking, email, and social media platforms. IP addresses from user registrations provide geolocation data that enables targeted social engineering. The combination of five distinct data types in this breach makes it particularly useful for building comprehensive victim profiles used in identity fraud.

What Was Exposed

• Email Address
• Username
• IP Address
• Birthday
• Password Hash (MD5)

Why This Matters

Birthdates combined with email addresses and cracked passwords give attackers the core pieces needed to impersonate victims to customer support teams at financial institutions and government services. Android app platform users often share accounts across devices and services, making their credentials valuable for attacks on mobile-specific platforms. Anyone who registered on MuMaYi and reused thier password or still uses the same birthdate as a security verification answer on other accounts faces ongoing risk from this breach. The dataset has been incorporated into aggregated credential collections used in automated attacks targeting Chinese-language platforms and international services.

How Database Breaches Work

Chinese Android app platforms in 2011 managed large user databases with varying levels of security maturity. An attacker who identified a SQL injection vulnerability or gained unauthorized database access could extract all user records in a single operation. MD5 hashing without salting meant that common passwords produced identical hash values, making bulk cracking via precomputed tables efficient. The resulting data, containing five fields per user, was particularly valuable because it enabled both credential stuffing and the more targeted identity-based attacks that require seperate pieces of personal information working together.

Check If You Are Affected

HEROIC offers a free identity scanner that searches over 400 billion records, including data from breaches like MuMaYi. Visit heroic.com to scan your email address and find out if your information was exposed.