What Is a Password Breach?

What Is a Password Breach?

A password breach occurs when passwords or other account credentials become exposed to an unauthorized person or are obtained through a security incident.

A breach can happen when an online service is compromised and information stored by that service is stolen. Credentials can also be exposed through phishing, malware, malicious software, or other attacks that target users directly.

A breach does not necessarily mean that every password belonging to every user was exposed. The information affected depends on the specific incident and the systems involved.

How Do Password Breaches Happen?

There are many ways credentials can become exposed. Some common examples include:

• Compromised services — An attacker gains unauthorized access to a company's systems or databases.
• Phishing — A user is tricked into entering their credentials into a fraudulent website or application.
• Malware — Malicious software can potentially capture credentials entered on an infected device.
• Credential stuffing — Previously stolen usernames and passwords are tested against other websites.
• Weak security practices — Poorly protected systems or improperly handled credentials can increase the risk of unauthorized access.

What Happens to Stolen Passwords?

Stolen credentials may be used in attempts to access the affected account or other accounts belonging to the same person.

This is one reason password reuse is particularly dangerous. If the same password is used for multiple services and that password is exposed in one breach, attackers may try it elsewhere.

Automated attacks can test large numbers of previously exposed username and password combinations against popular online services. This type of attack is commonly known as credential stuffing.

Why Password Reuse Makes Breaches Worse

Consider an example where someone uses the same password for an online shopping account, a social media account, and their email account.

If the shopping service suffers a breach and that password becomes known, the attacker now has a password that may work on the other accounts as well.

Using a different password for every important account limits the damage that can result from a single exposed password.

You can learn more about this topic in our article: Why You Should Never Reuse Passwords .

What If Passwords Are Hashed?

Many online services do not store user passwords as plain text. Instead, passwords are typically processed using password hashing techniques before being stored.

Hashing and encryption are different technologies. Encryption is designed so that authorized users or systems can decrypt the original information using the appropriate key. A properly designed password-hashing system is intended to make it difficult to recover the original password from the stored hash.

However, a breach can still be serious even when passwords are hashed. Attackers may attempt to guess passwords and compare the resulting hashes against stolen password hashes. Weak or commonly used passwords can be particularly vulnerable to these attacks.

How Can You Tell If a Password Was Breached?

Some services notify users when an account has been affected by a security incident. Security researchers and breach-notification services may also provide information about known data breaches.

Some password managers include breach-monitoring or password-checking features that can help identify passwords associated with known breaches.

Keep in mind that no breach database can guarantee that it contains every credential that has ever been exposed. The absence of a password from a particular database does not prove that the password has never been exposed.

What Should You Do After a Password Breach?

If you learn that an account has been affected by a breach, change the password for that account as soon as practical.

If you reused that password anywhere else, change those passwords too. Each account should have its own unique password.

You should also consider enabling multi-factor authentication when the service supports it. This provides an additional authentication factor beyond the password.

For important accounts, such as your primary email account, take particular care. Your email account may be used to reset passwords for many other services.

How Can a Password Manager Help?

Remembering a different strong password for every account can be difficult. A password manager can generate and securely store unique passwords so you do not have to memorize them all.

Instead of creating predictable variations of the same password, you can use a different randomly generated password for each service.

If one service is breached, the exposed password is then less useful against your other accounts because the other accounts use different credentials.

What Is a Breach Scan?

Some password managers provide a feature commonly called a breach scan. This type of feature can compare information associated with your stored passwords against known breach information.

Privacy-preserving approaches can be used to perform these checks without sending the complete password to an external service. One example is k-anonymity, which allows a system to perform certain breach checks without directly transmitting the full password.

The exact implementation varies between products, so it is worth checking how a particular password manager performs its breach checks and what information leaves the device.

Password Breaches and KeenPassword Vault

KeenPassword Vault includes a Breach Scan feature designed to help identify passwords associated with known breach data.

The scan uses a k-anonymity approach. Your actual passwords and master key are not sent over the network during the breach check.

KeenPassword Vault is also designed as a 100% offline password manager. Your vault remains stored locally on your Windows computer rather than being synchronized to a cloud account.

Keeping passwords unique, using strong credentials, and periodically checking for known exposure are all useful parts of maintaining good password security.

The Bottom Line

A password breach can expose credentials that attackers may attempt to use against the affected account or other accounts.

One of the most effective ways to reduce the impact of a breached password is to use a unique password for every account. A password manager can make this practical by generating and storing strong, unique passwords.

If an account is affected by a breach, change its password, change any reused passwords elsewhere, and consider enabling multi-factor authentication where available.