Your Hotmail.jp Password Is Exposed: 4,246 Credentials Leaked

In June 2026, HEROIC analysts discovered a stealer log file targeting Hotmail.jp users circulating on a public Telegram channel. The dump contains 4,246 records, each linking a Hotmail.jp email address to a plaintext password and the URL of a service where the credentials were entered. Hotmail.jp is the Japanese localization of Microsoft's email service, and the exposure of these credentials places thousands of Japanese internet users in immediate danger of account takeover.

If you have ever registered a Hotmail.jp email address, your password may already be in the hands of threat actors. The data is publicly available, unencrypted, and ready to use.

Why Plaintext Passwords Leave No Time to React

The 4,246 passwords in this dump are stored in their original, unencrypted form. There is no hashing layer to slow down attackers, no encryption to bypass, and no additional authentication challenge. Each credential is a direct, working key to the associated account.

The urgency is real. Automated attack tools can process thousands of credential pairs per minute, testing each one against Microsoft's login infrastructure and then branching out to other popular services. For every victim who reused their Hotmail.jp password elsewhere, the compromise extends to every account sharing that password.

Hotmail.jp accounts are part of the broader Microsoft account ecosystem, which means a single compromised credential can provide access to Outlook email, OneDrive cloud storage, Microsoft Teams, and any other Microsoft service linked to that account. The scope of potential damage from one stolen password is enormous.

What Was Exposed in the Hotmail.jp Dump

• Email Addresses — Hotmail.jp email accounts used by Japanese users as primary Microsoft account identifiers, potentially linked to OneDrive, Skype, Xbox, and other Microsoft ecosystem services.
• Plaintext Passwords — Unencrypted passwords captured by infostealer malware directly from victims' devices, usable for instant account access without any decryption step.
• URLs — The websites and services where these credentials were entered, revealing each victim's online service usage and enabling precisely targeted exploitation.

Why 4,246 Exposed Japanese Email Accounts Raise the Stakes

Hotmail.jp users in Japan rely on their Microsoft accounts for a wide range of daily activities, from personal email correspondence to cloud document storage and professional communications. The 4,246 compromised accounts in this dump represent a significant exposure within the Japanese Microsoft user community.

Japanese internet users are frequent targets for social engineering campaigns that exploit compromised email accounts. An attacker with access to a Hotmail.jp inbox can send convincing phishing messages to the victim's contacts, access sensitive documents shared through OneDrive, and intercept password reset emails from banking and financial services.

The financial implications are substantial. Japan has a highly digitized economy, and compromised email accounts can serve as entry points to online banking, e-commerce accounts, and mobile payment services that are deeply integrated into daily life.

How Stealer Logs Target Users Across Borders

The Hotmail.jp credentials were not stolen by hacking Microsoft's servers. Instead, infostealer malware running on individual devices in Japan and elsewhere captured these credentials as users logged into their accounts. The malware silently extracts saved passwords from web browsers, autofill databases, and email client configurations.

Infostealers targeting Japanese users often spread through localized phishing campaigns, fake software download sites offering popular Japanese applications, and malicious browser extensions. The malware operators do not discriminate by geography — they harvest credentials from every infected device worldwide and then sort the data by email domain for targeted distribution.

The resulting log files are shared through Telegram channels where they reach an international audience of threat actors. A Hotmail.jp collection attracts particular interest from attackers specializing in Japanese markets, who understand local banking systems and know which services will yield the highest returns from compromised accounts.

Check If Your Hotmail.jp Credentials Were Exposed

Time is critical when plaintext credentials are circulating freely. Every day that passes without action is a day in which attackers could be accessing your email, reading your messages, and compromising your linked accounts. Do not wait for signs of unauthorized activity to take action.

HEROIC offers a free breach scanner that searches more than 400 billion records from known breaches and stealer log distributions worldwide. Enter your Hotmail.jp email address to check whether your credentials appear in this dump or any other compromised dataset. If your data is found, change your Microsoft account password immediately, review your account's recent activity log, and activate two-factor authentication to prevent future unauthorized access.