A leak notice arrived. What to do today, this week, and in 30 days
You get an email: "We are writing to inform you that your personal data may have been leaked." Do you know what to do next — and by when? Earlier this year, Japan's government asked citizens to "protect your own information." The public reaction was blunt: companies leak — how is an individual supposed to protect anything? Fair. The leaking side is the companies. But one thing IS in your hands:…
You receive an email informing you that your personal data may have been leaked. It is crucial to know what steps to take next, and by when. Earlier this year, Japan's government requested citizens to protect their own information, but the response was critical: companies are the ones leaking information. However, there is something in your control, and that is building a state where a leak doesn't spread.
To assist you in this, I have created a small tool that you can access online. It runs solely on your device, and no data is shared; the source code is available for public review as well.
In 2026, Japan's listed companies have already announced ten breaches, with each affecting more than 1 million records. This is the highest pace on record. Additionally, ransomware incidents have increased to 123 in the first half of 2026, which is the highest for any half-year. Over 90% of unsolved unauthorized-access cases have involved the abuse of IDs and passwords.
Most attackers don't break defenses; instead, they steal a key and gain access. Four main entry points are identified: known vulnerabilities, unpatched systems, stolen credentials, a supplier or shared platform falling, and human judgment.
The impact you face depends on the type of data leaked. The most alarming discovery is that a leak initiates a chain on the same day. A compromised password is tested on other services within hours, potentially exposing your email, shopping accounts, and more. With credit card information, the compensation depends on how quickly you report, with a typical 60-day window.
Bank accounts and PINs can be manipulated through fraudulent voice calls, as the attacker knows your name and branch. License images are flagged for loan applications and account openings, and change does not alter the first 11 digits of the number. Name, address, and phone information may not be catastrophic but can strengthen scams that rely on knowing too much about you. Be vigilant for a month or two following any leak.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
