In November 2025, Nikkei, a major media corporation, experienced a data breach that compromised the personal information of over 17,000 individuals. If you're among those affected, it's crucial to understand what was exposed, the potential risks, and how to protect yourself moving forward. This guide will provide you with the necessary details and steps to safeguard your information.
What Datapoints Were Leaked?
The Nikkei breach in November 2025 was the result of unauthorized access to the company's Slack platform. It wasn't just some harmless system log—actual personal data got exposed. Here’s what you need to know:
Names and Email Addresses: The breach affected 17,368 individuals. Names and email addresses were part of the data accessed. If your contact details were tied to Nikkei’s Slack, they could be out there.
Chat Histories: This isn’t just about contact information. Chat logs were also exposed. Depending on your level of participation, this could mean anything from casual team banter to more sensitive project discussions.
What Wasn’t Exposed: Importantly, no confidential journalistic sources or investigative activities were compromised. Nikkei confirmed that information tied to source protection and journalism integrity stayed safe.
If your name, email, or old conversations were in Nikkei’s Slack, they may now be in the hands of people you’d never want reading them. While it’s not the same as a leak of passwords or financial data, the exposure of chat histories and contact details can still open doors for bad actors.
Should You Be Worried?
When news of a data exposure breaks, it’s easy to brush it off—until you realize how quickly things can spiral. With the Nikkei breach, the real question is: what could happen with the information that slipped out?
The Immediate Fallout: Phishing and Social Engineering
Phishing attacks are likely the first threat to emerge. When cybercriminals get their hands on contact details—names, emails, maybe even organizational roles—they have what they need to send convincing fake emails. These aren’t your run-of-the-mill scams full of typos. Attackers now craft emails that look like the real deal, sometimes even referencing specific projects or colleagues. All it takes is one distracted click for malware to sneak in or sensitive credentials to be handed over.
Targeted phishing (spear phishing) can trick even cautious employees.
Malware-laden attachments often arrive disguised as work documents.
Credential harvesting is a real risk; attackers may set up fake login pages.
Identity Theft and Business Email Compromise
Beyond phishing, the risk of identity theft looms large. Leaked personal or business information can be pieced together to impersonate staff, open fraudulent accounts, or siphon off company resources.
Business Email Compromise (BEC) is especially dangerous:
Attackers pose as executives or trusted partners.
They send urgent requests for wire transfers or sensitive data.
Since the emails seem to come from inside the organization, employees may not think twice.
The consequences? Financial loss, reputational damage, and even legal headaches for affected businesses.
Regulatory Angle: What the Law Says
Here’s where things get interesting. The Nikkei incident, as reported, doesn’t fall under a regulatory breach according to Japan’s Personal Information Protection Law. The data exposed didn’t meet the threshold for “personal information” as defined by law. Legally, Nikkei might be in the clear.
But let’s not kid ourselves—just because it’s not illegal doesn’t mean it’s harmless. Information that seems mundane can still be weaponized. Privacy isn’t just about ticking boxes; it’s about respecting the trust people put in a company.
Staying Proactive: What You Can Do
The best defense is preparation. Using privacy-focused tools like Cloaked helps you reduce the risk from exposed data. By generating disposable emails and phone numbers, you can keep your real contact details safe, even if a breach happens elsewhere. It’s an easy way to put a barrier between you and potential attackers—without disrupting your workflow.
What Should Be Your Next Steps?
When your data is at risk, every minute counts. Acting fast can make all the difference between a close call and real trouble. Here’s what you need to do—step by step.
1. Change Your Passwords Immediately
Prioritize accounts that matter most: Start with email, financial accounts, and anything tied to your identity.
Use strong, unique passwords: Don’t recycle old ones. Consider a password manager if remembering dozens of passwords feels like juggling chainsaws.
Enable two-factor authentication (2FA): This adds an extra layer of security—think of it as locking your door and then bolting it.
2. Monitor Your Accounts Closely
Check for unfamiliar activity: Look for logins from odd locations, strange emails, or messages you didn’t send.
Set up alerts: Most banks and major platforms let you get notifications for suspicious activity. Turn these on if they’re not already.
Review linked accounts: Sometimes, hackers get in through third-party apps. Unlink anything you don’t use.
3. Use Privacy Tools for Added Protection
Sometimes, basic steps aren’t enough. Tools like Cloaked offer practical ways to keep your personal data shielded:
Create masked emails and phone numbers: Cloaked generates alternate identities to use online, so your real info stays private—even if a site is compromised.
Control and retract shared data: With Cloaked, you decide what information is shared and can pull it back anytime.
Centralized privacy dashboard: See where your data lives, who has access, and manage permissions from one place.
These tools are designed for people who want more than just hope as a defense strategy.
4. Stay Alert for Suspicious Activity
Watch for phishing attempts: Hackers love to piggyback on recent breaches. Double-check unexpected emails or texts—even those that look legit.
Don’t ignore small red flags: A single odd notification can be the tip of the iceberg.
Educate those around you: If your account is at risk, friends and family could be next in line. Share what you know.
5. Report and Document
Contact affected companies: Let them know your account could be compromised. They may have specific guidance or support channels.
Keep records: Save emails, screenshots, and details. If things escalate, having proof will save you time and headaches.
Taking these steps doesn’t just help after a breach—it makes you harder to target in the first place. Stay sharp, act quickly, and use the right tools to put control back in your hands.
Cloaked FAQs Accordion
Frequently Asked Questions
First, change your passwords—especially if you've reused them across sites. Then enable two-factor authentication (2FA) on all key accounts. Review your account and credit activity regularly for any unusual behavior. If suspicious actions surface, consider freezing your credit and alerting your bank. To proactively reduce exposure in the future, tools like Cloaked can mask your personal information before breaches happen.
Cloaked provides you with disposable emails, phone numbers, and payment details, making it harder for bad actors to access your real identity. These tools help you safely sign up for services, communicate, and shop online without putting your core identity at risk.
Commonly targeted data includes full names, email addresses, phone numbers, birthdates, physical addresses, login credentials, and payment info. Tools like Cloaked help shield this information by providing secure, masked alternatives.
Always be skeptical. Malicious links are one of the most common ways hackers infect devices or steal data. Avoid clicking unless you can verify the source. Services like Cloaked can add layers of security so your real contact info isn’t exposed even if you make a mistake.
Using the same contact info across platforms makes it easy for attackers to build a full profile of you. If one platform gets breached, all your accounts can be at risk. That’s why Cloaked allows you to use different, secure contact methods for each service.
At Cloaked, we believe the best way to protect your personal information is to keep it private before it ever gets out. That’s why we help you remove your data from people-search sites that expose your home address, phone number, SSN, and other personal details. And to keep your info private going forward, Cloaked lets you create unique, secure emails and phone numbers with one click - so you sign up for new experiences without giving away your real info. With Cloaked, your privacy isn’t a setting - it’s the default. Take back control of your personal data with thousands of Cloaked users.
*Disclaimer: You agree not to use any aspect of the Cloaked Services for FCRA purposes.
