What to do step by step when you discover that your data has been leaked

¿What to do step by step when you discover that your data has been leaked? You may have checked a data leak website or received a warning from a company, and suddenly you discover that Your passwords or personal data have been leakedThe fear is inevitable: you think about your bank, your social networks, your email… and everything you could potentially lose.

The bad part is that There's no way to "erase" that leak from the internet.If your data has already been stolen and shared, it will continue to circulate. The good news is that if you act quickly and strategically, you can significantly reduce the damage and make life difficult for cybercriminals. Let's see, step by step, how to do it.

What exactly is a data breach and why is it so serious?

When we talk about a data leak or breach, we are referring to a cybersecurity incident in which Personal or corporate information is exposed without authorization.This exposure can be due to a direct hacker attack, human error, technical failures, or even the theft or loss of devices.

A data breach can contain all kinds of information, from seemingly insensitive data to extremely sensitive information. Among the things an attacker might find are: personal identification data such as name and surname, addresses, telephone numbers, ID card or tax identification number, as well as professional information associated with a company.

Leaks are also very common financial data such as account numbers, credit or debit cards and bank transaction detailsWith this type of information, the leap to fraudulent purchases, transfers, or contracting of services in your name is a matter of minutes if you don't react in time.

Another critical block is the usernames and passwords for accessing all types of platformsEmail, social media, cloud storage services, online stores, or even corporate tools. If you also use the same password on multiple sites, a single breach could give them access to half the internet.

Do not forget the health data, medical records, or clinical reportswhich in some sectors are also affected by leaks. And, in the case of companies, corporate information such as customer lists, intellectual property, source code, or sensitive internal documentation can be pure gold for an attacker.

How leaks happen: it's not all the hackers' fault

When we talk about data breaches, we tend to always think of large cyberattacks, but the truth is that Leaks can have many different originsUnderstanding them helps you better assess the real risk you are exposed to, both personally and professionally.

A very significant part of the leaks is due to cyberattacks targeting companies that store our dataAttackers exploit vulnerabilities in their systems, deceive employees with social engineering techniques, or take advantage of insecure configurations to download entire databases and then sell or publish them.

However, a significant number of incidents originate from seemingly “innocent” human errors: sending confidential information to the wrong recipient, sharing sensitive documents with public permissions, copying unencrypted files to the wrong places, or accessing data that should not be accessible.

Leaks also occur when Devices containing unencrypted information are lost or stolensuch as laptops, USB drives, or external hard drives. If these devices are not adequately protected, anyone who finds them can access the contents and extract personal or corporate data.

Finally, there is the risk of the malicious internal usersEmployees, former employees, or collaborators who, for revenge, financial gain, or other reasons, deliberately access data and share it with third parties. Although less frequent, these leaks can be especially damaging because the attacker has a thorough understanding of the system.

What is your data used for when it is leaked?

Behind a data leak there is usually a very clear objective: to obtain an economic or strategic benefitYou won't always see the consequences immediately, but that doesn't mean your data isn't being used in the background.

The most obvious use is the selling databases on the dark webIn these forums, packages of millions of emails, passwords, phone numbers, credit card numbers, or purchase histories are bought and sold, which are then exploited in massive fraud campaigns or resold over and over again.

With certain types of personal data (name, ID number, address, date of birth, etc.) attackers can carry out highly credible identity theftsThey can open accounts in your name, contract services, register supplies, or use your identity to deceive third parties, both individuals and companies.

Contact details, especially email address and mobile number, are used extensively for spam campaigns, phishing, smishing and other scamsThe more they know about you (for example, if they have also obtained your name or the company you work for), the more they will personalize the messages to make them seem legitimate.

In the case of companies, a major leak can be the prelude to espionage, blackmail, or sabotage attacksAttackers may threaten to publish the stolen information if a ransom is not paid, sell it to competitors, or use it to prepare more sophisticated attacks against the organization.

How to know if your data has been compromised

Often you don't find out about a leak until the company itself notifies you or you read the news in the press, but You shouldn't just wait to be told.There are several ways to detect potential exposures of your data with some initiative on your part.

A simple option is to use alert services like Google AlertsYou can set up alerts for your name, primary email address, company name, or even phone numbers. Every time they appear on a new page indexed by Google, you'll receive an email; it's not perfect, but it can give you clues about unexpected mentions.

To check if an email address or phone number has been in any known data breach, you can use tools such as Have I Been PwnedYou enter your email or phone number and the service tells you if it has appeared in previous massive data breaches and in which ones, helping you assess the risk and make decisions.

In the corporate sphere, there are professional monitoring and active listening solutions These services monitor social media, forums, and websites for mentions of a brand, corporate email domains, or internal data. They are often key to quickly detecting a potential reputational crisis or data breach.

In addition, some security suites and tools such as identity theft monitoring services Integrated into solutions like Microsoft Defender, they offer alerts if they detect that your email or data appears in stolen datasets, and can guide you through the steps to remedy it.

Immediate first steps if you discover a leak

When you confirm or seriously suspect that your data has been leaked, the first thing to do is Stay calm and act methodicallyPanic often leads to mistakes, and here you need to be cool and organized to plug holes as soon as possible.

First of all, try to find out in as much detail as possible what type of data has been affectedSometimes the company provides specific public information; other times you'll have to ask directly. For security reasons, it's advisable to assume that any data you share with that service may be compromised.

While you gather information, you should get some work done in advance: Change the related passwords immediatelyStarting with the affected service and continuing with all others where you use the same or a very similar password, this measure effectively stops many automated login attempts that try different combinations on various websites.

If you haven't activated it yet, now's the time to do so. Two-step verification or multi-factor authentication on all important servicesWith this system, even if someone has your password, they will need a second factor (SMS code, authenticator app, physical key, etc.) to log in, which stops 99% of automated password attacks; and take this opportunity to review the privacy settings of your messaging apps.

Finally, in this initial phase it is advisable Review the latest logins to your most sensitive accounts. (primary email, online banking, social media, major online stores) to detect logins from unusual locations or devices. Many platforms allow you to log out of all devices and start fresh with new credentials.

What to do depending on the type of data that has been leaked

Not all leaks have the same impact; The specific actions depend heavily on the type of data exposed.It's not the same as having an old email you no longer use leaked as having your ID card and active bank card leaked.

If what has been stated is mainly passwords or username and key combinationsYour absolute priority is to change them. Do so on the affected service and any other where you've reused the same or a very similar password. After that, seriously consider using a password manager that generates long, unique, and strong passwords.

When the filtered includes email address and/or phone numberYou should anticipate an increase in spam, suspicious calls, phishing messages, and smishing. It's highly recommended to use alternative email addresses and backup phone numbers for occasional registrations whenever possible, reserving your primary email and personal mobile number only for critical services.

If the information presented reaches name and surname, postal address, ID card or other identification documentsThe risk of identity theft is higher. In these cases, it's advisable to do "egosurfing" from time to time; that is, search your name online to detect fake profiles, strange ads, or suspicious activity that might be impersonating you.

In the most delicate scenario, when leaks have occurred bank details or your cardYou should contact your bank as soon as possible. Explain the situation so they can cancel or block the card, monitor for unusual activity, and, if necessary, open an internal investigation. In many cases, it will be necessary to issue a new card with a different number.

If you live in a country where this is relevant and you believe that data such as your Social Security number or other key identifiers have been compromised, it's a good idea activate some type of monitoring of your credit report And, if you detect suspicious activity, request a temporary block on new credit lines in your name.

How to protect your financial privacy after a leak

When money is involved, every minute counts. That's why, if the leak suggests that Payment data or access to financial services have been affectedIt is advisable to take a series of additional measures focused on your finances.

The first thing to do is ask your bank to Immediately block potentially affected cards and issue new ones.This way, even if someone has obtained your old card number, they will not be able to continue using it for online purchases or cash withdrawals.

At the same time, you should Carefully review your latest bank transactions and card transactions.Pay attention to small charges or services you don't recognize, as many criminals test with small amounts before making larger purchases. If you see anything suspicious, report it to your bank immediately.

If the scope of the leak is large or includes particularly sensitive data, it is advisable Activate alerts on your bank and cards for any transactionMany entities allow you to receive an SMS or push notification for each payment, which is very useful for detecting unauthorized transactions in a matter of seconds.

In countries where a credit reporting system exists, consider Request a free report and check if anyone has tried to open lines of credit in your name.And if you confirm that there is a real risk, you can request a temporary block on your history so that no new applications are approved without your intervention.

Monitor your accounts and detect misuse

The impact of a breach isn't always seen on the first day; sometimes the attackers They wait weeks or months before exploiting the data.Therefore, once the urgent matters are resolved, it's time to remain vigilant for a while.

During the following weeks, it is advisable closely monitor the activity of your most important accountsCheck your email, social media, online banking, marketplaces, payment services like PayPal, etc. Make sure no new shipping addresses, personal information, or payment methods have been changed.

If you use the same password across multiple services (something you should stop doing now), attackers can cross-reference credentials to try to gain access. all kinds of websites with your email and password leakedThis practice, known as credential stuffing, is massive and automated, so the more passwords you change, the fewer doors they'll have open.

It's important to get used to Review login prompts from new locations or devicesMany platforms send emails when they detect unusual login activity; don't ignore them. If it wasn't you, change your password and log out of any active sessions.

Finally, strengthen your “mental filter”: Be especially wary of messages that ask for personal information, passwords, or verification codes.Even if they appear to be from your bank, your mobile provider, or a well-known company, if you have any doubts, go directly to the official website by typing the address into your browser or call the official phone number. Never reply from the link or number you receive in the message.

User rights and possible legal actions

When a leak directly affects you, you don't just have to think about technical measures; you also You have legal rights as the data subject.In the case of companies that process data of citizens of the European Union, the General Data Protection Regulation (GDPR) applies.

If the organization that suffered the breach handles your data, it is obligated to notify the competent supervisory authority within a maximum period of 72 hours since becoming aware of the incident, unless the leak is unlikely to affect people's rights and freedoms.

Furthermore, when the leak is serious or could have a significant impact, the company must inform the affected people clearlyexplaining what has happened, what type of data has been compromised, what measures they are taking and what they recommend users do.

If you believe that the company has not adequately protected your data or has not acted diligently When dealing with the incident, you can file a complaint with the Spanish Data Protection Agency (AEPD). This agency can initiate sanction proceedings with significant fines for the responsible entity.

In certain cases, especially if you can demonstrate economic or moral damages resulting from the leak, there is also the option of claim compensation for damages through civil proceedings. For this, it is usually advisable to seek specialized legal advice.

Reputational crisis management when data is exposed

Beyond the technical and legal aspects, a major leak can have a direct impact on your personal reputation or your company's imageSometimes the harm comes not so much from the content itself, but from how it is perceived publicly.

The first step is to calmly analyze the scope of the exposure: What information has been released, where is it published, and who can see it?It's not the same to have your email appear on a technical list as it is to have private photographs or especially sensitive data such as affiliations, preferences or health histories disseminated.

In some cases, especially when it comes to personal content or data published without your consentIt is possible to request that platforms remove this information or restrict access to it. You can also ask search engines, such as Google, to deindex certain URLs related to your name based on the so-called "right to be forgotten."

At a corporate level, if the leak generates a reputational crisis, it may be necessary launch a clear and transparent communication strategyPublicly explain what happened, what measures have been taken, and how information will be better protected in the future. Hiding or minimizing the problem usually makes it worse in the medium term.

In particularly complex situations, some organizations resort to digital reputation and cybersecurity consultants that help monitor mentions, develop a contingency plan and implement mitigation actions, such as generating positive content that displaces negative news in search results.

Measures to prevent future leaks and reduce the impact

While you can never have zero risk, you can greatly reduce the probability and impact of future leaks adopting good habits and using the right tools in your digital daily life.

The first pillar is the use of secure, unique passwords managed with a good password managerAvoid short, predictable passwords or those based on personal data. Ideally, use phrases or long combinations of letters, numbers, and symbols, different for each important service.

Second, get used to Enable two-factor authentication whenever possibleToday, most major services (email, networks, banking, cloud storage) offer this option, which exponentially increases security with very little extra effort.

Another key measure is Keep all your devices and programs up to dateMany updates include security patches that fix known vulnerabilities; delaying them leaves doors open that attackers know how to exploit very well; also, check how prevent them from sending usage data your connected devices.

It is also convenient Perform regular backups of your most important informationThis applies to both encrypted external drives and reliable storage services. This way, if you suffer a ransomware attack or a data breach that forces you to delete accounts, you can recover your essential data without giving in to blackmail; if you need to move information, learn how to migrate your data between services.

Finally, don't underestimate the value of training: Understanding how phishing, smishing, vishing, and other scams work This will give you a significant advantage against most attempts at deception. In business environments, organizing cybersecurity awareness sessions for employees is one of the most cost-effective investments you can make.

Although data leaks have become all too common and it's impossible to be 100% secure, Be clear about the steps to follow, know your rights, and apply good digital security practices It makes the difference between a minor scare and a serious long-term problem. Reacting quickly, thoroughly reviewing what has been affected, and strengthening your security measures is the best way to minimize the damage if you experience a data breach.