docomo.ne.jp Users Targeted: 10,889 Passwords and Emails Leaked

In June 2026, HEROIC analysts identified a stealer log targeting users of docomo.ne.jp, one of Japan's largest mobile email providers. Uploaded to a public Telegram channel, the file exposed 10,889 records containing email addresses, plaintext passwords, and browsing URLs stolen from infected devices. The breach data was verified and added to the HEROIC database on July 15, 2026.

Why Japanese Mobile Email Users Face Heightened Risk

The docomo.ne.jp domain belongs to NTT Docomo, Japan's leading mobile carrier. Users of this email service often link their accounts to mobile payments, app store purchases, and personal banking. With 10,889 plaintext passwords now in the hands of attackers, every connected service becomes a potential target. The stolen browsing URLs also reveal which financial and shopping platforms each victim frequents, giving criminals a precise attack plan.

What Was Exposed in This Stealer Log

• Email addresses belonging to docomo.ne.jp mobile email users
• Plaintext passwords stored in readable form with zero encryption
• Browsing URLs revealing the websites and services each victim accessed

Why This Data Powers Credential Stuffing and Identity Theft

When attackers have both an email address and its plaintext password, they can test that combination across hundreds of other services using automated tools. This technique, known as credential stuffing, exploits the common habit of reusing passwords. For docomo.ne.jp users, this means banking apps, social media accounts, cloud storage, and online shopping profiles could all be compromised from a single stolen credential. The risk of full identity theft grows with every account an attacker unlocks.

How Stealer Logs Silently Harvest Mobile User Credentials

Stealer logs are produced by infostealer malware that infects computers and smartphones without the owner's awareness. The malware often spreads through deceptive app downloads, phishing messages, or malicious links shared on social media. Once active, it captures login credentials saved in browsers and apps, records keystrokes, and logs browsing history. The collected data is bundled into files and distributed on platforms like Telegram, where buyers use the credentials for fraud and unauthorized access.

Check If Your docomo.ne.jp Account Was Compromised

If you use a docomo.ne.jp email address, your credentials could be among the 10,889 exposed records. HEROIC tracks over 400 billion compromised records from breaches, stealer logs, and dark web sources worldwide. Use HEROIC's free breach scanner to search your email and determine whether your account data appears in this leak or any other known breach.