Common types of data breaches and tips on how to prevent them

A data breach means that attackers have successfully compromised your company’s cyberdefenses and gotten their hands on some corporate data. A serious data breach could ruin your business’ reputation, let alone cost a fortune to recover from. Knowing the common ways that cybercriminals breach data security will help you keep your company’s defenses resilient to attacks.

What is a data breach?

During the third quarter of 2024 alone, data breaches exposed more than 422 million user accounts worldwide, while the cost of a data breach in 2024 reached a global average of USD 4.88 million.

You might think a data breach always has some malicious intent behind it. However, a data breach can sometimes happen due an accidental data leak or human error.

The most common types of data breaches

A data breach may easily become your company’s most expensive problem. Check out our comprehensive list of the most common types of data breaches and their causes so that you can direct your security effort toward preventing these threats.

Malware

Malware is any harmful software (program or file) that cybercriminals develop to steal data, cause damage to computers and systems, or deprive legitimate users of their access to the system or information. The number of malware attacks globally has been rising steadily since 2021, with 6.06 billion cases reported in 2023.

Though numerous types of malware can bring about a data breach, they spread in similar ways. Typically, you may catch a malware infection when you do the following:

• Download an infected file or app.
• Click on a malicious link or ad.
• Install software from unreliable sources.
• Use legitimate software that has vulnerabilities that attackers may exploit. This includes postponing software updates designed to patch up security flaws.
• Fall for a phishing attack or scam.

Let’s explore the most common and damaging types of malware.

Ransomware

Ransomware encrypts or locks data on your device and demands a ransom for the decryption key, effectively locking you out of your own system. In businesses, a ransomware infection can escalate into a corporate data breach if attackers steal sensitive information before encrypting it, threatening to expose or sell the data if you don’t pay up.

Spyware

Once spyware infects your device, it gathers information you store on it, including personal and corporate data, and sends it to the attackers. Typically operating in the background, spyware can track your browsing habits, capture keystrokes, and monitor online activities without your knowledge.

Viruses

Viruses are malicious software programs that attach themselves to legitimate files or applications, spreading and causing harm either when you execute the malicious file or executing automatically by exploiting operating system or software vulnerabilities.

Worms

Worms are self-replicating malware that spreads independently without needing a host file or program, often exploiting network vulnerabilities to infect other systems automatically.

Adware

Adware is a type of software that delivers intrusive advertisements to users. Typically, it collects data or redirects users to specific websites, often malicious.

Trojan horses

Trojan horses are a particularly sneaky type of malware that downloads onto your computer disguised as legitimate software. They are capable of stealing data and installing additional malware.

Rootkits

A rootkit is a collection of malicious software that hackers hide on your computer to reach areas otherwise inaccessible to them and to take control of your system. Rootkits operate at a deep system level, often hiding within core operating system files, making them invisible to standard security tools and able to bypass typical removal methods.

Keyloggers

Keyloggers are malicious software or hardware that secretly keep track and record your every keystroke. This way, they can capture sensitive data like passwords, messages, and credit card details.

Social engineering

Social engineering is the psychological manipulation of people to make them compromise data security. Criminals often create fake emails, ads, or websites designed to look legitimate, tricking you into revealing personal information, clicking a malicious link, or downloading harmful attachments, which may all result in a corporate data breach.

Phishing attacks

Phishing attacks are one of the most common social engineering methods that come in different forms:

• Spear phishing. In spear phishing, attackers use personalized information to target a specific person, group, or organization. They aim to coerce you into sharing sensitive information, downloading malware, or sending them money.
• Email spoofing. Cybercriminals send fake emails that appear to come from a trusted source to trick you into revealing sensitive information.
• Whaling attacks direct their effort towards high-profile companies and individuals, such as executives, to gain access to confidential corporate or client data.

SQL injection

In SQL injection, attackers inject malicious SQL code into an entry field on a website or application, tricking the database into revealing unauthorized information. This way, they are able to access, modify, or delete data, potentially compromising the security and privacy of the entire database.

Password attacks

A password attack is just what it sounds like — a hacker’s attempt to steal your password by using one or several methods described below.

Credential stuffing

Credential stuffing is the use of automated tools to try stolen username and password combinations from previous data breaches in website login forms with the goal of gaining unauthorized access to user accounts.

Password cracking

Password cracking is about trying to access a password-protected system by systematically guessing or decrypting passwords. To crack a password, attackers may use methods like brute force, dictionary attacks, or rainbow tables.

Brute-force attacks

In a brute-force attack, cybercriminals attempt all possible combinations of characters until they successfully guess the correct password. It’s an effective yet time-consuming password-cracking method.

Rainbow table attacks

Rainbow table attacks use precomputed tables of hashed password values to quickly match and reveal plaintext passwords, significantly reducing the time needed to crack them. By comparing stored password hashes against these tables, attackers can bypass the need for repetitive hashing attempts. This method is especially effective against weak or commonly used passwords.

Insider threats

Insider threats are risks posed by individuals within an organization who, intentionally or not, compromise sensitive information, security, or operations.

Data leakage

Data leakage is an exposure of confidential or protected data. An individual within an organization could intentionally or unintentionally share sensitive information with unauthorized individuals or through unsecured channels. Apart from human error, data may also leak due to software vulnerabilities or poor data security measures.

Data exfiltration

Data exfiltration is deliberate, unauthorized transfer of data from within an organization to an external destination or third party.

Advanced threats

Advanced threats are sophisticated, targeted cyberattacks designed to evade traditional security defenses and infiltrate networks undetected. These threats often employ stealthy techniques, persistence, and customized malware.

Cyber espionage

Cyber espionage is a form of digital spying. It involves the use of cyber tactics to covertly gather confidential information from governments, corporations, or individuals, often for strategic or competitive advantage. Nation-states, state-sponsored groups, and highly skilled threat actors opt for cyber espionage to target intellectual property or classified information.

Advanced persistent threats (APTs)

Advanced persistent threats are targeted, covert cyberattacks in which intruders gain unauthorized access to a network and remain undetected over an extended period. Typically, nation-states and organized crime groups conduct these highly sophisticated attacks.

Zero-day exploits

In zero-day exploits, attackers take advantage of unknown security vulnerability in computer software, hardware, or firmware. The software vendor and security community don’t yet know about these vulnerabilities, leaving no time (“zero days”) for developers to patch them, which, in turn, allows attackers to infiltrate systems before defenses can be implemented.

Supply chain attacks

In supply chain attacks, cybercriminals infiltrate an organization by compromising its external partners or third-party vendors that have access to the organization’s systems or data. For example, by targeting trusted suppliers, attackers can introduce malicious code or vulnerabilities to a target’s system or network.

Network and session attacks

Network and session attacks target active network connections and communication sessions to intercept, alter, or hijack data.

Man-in-the-middle attacks

A man-in-the-middle attack happens when a cybercriminal secretly intercepts and potentially alters the communication between two parties who think they’re communicating directly, or between a user and an application. It’s like someone eavesdropping on a private conversation, possibly even changing the information before it reaches the other person.

Session hijacking

Session hijacking involves taking over an active internet session between a user and a web application. This allows the attacker to act as the legitimate user and, as a result, gain unauthorized access to sensitive information and actions within the session.

ARP spoofing

ARP spoofing is a technique where an attacker sends falsified (spoofed) address resolution protocol (ARP) messages onto a local area network to link their device’s MAC address with the IP address of a legitimate host. This allows the attacker to intercept, modify, or stop data intended for that IP address.

DNS attacks

DNS attacks exploit vulnerabilities in the domain name system (DNS) to compromise the availability, stability, or integrity of DNS service. By disrupting or manipulating DNS, attackers can redirect users to malicious websites, intercept sensitive data, inject malware, or enable further attacks. Common types include DNS spoofing, DNS amplification attacks, DNS tunneling, and pharming.

• DNS spoofing is an attack where malicious actors manipulate DNS records or responses to redirect users to malicious websites without their knowledge.
• A DNS amplification attack is a type of distributed denial-of-service (DDoS) attack that exploits vulnerable DNS servers by sending small, spoofed requests that elicit large responses. These amplified responses overwhelm the target server with massive amounts of data, causing network disruption or service outages.
• DNS tunneling routes DNS requests to an attacker’s server, creating a covert channel for command-and-control communication and data exfiltration, often blending with legitimate traffic to evade detection.
• Pharming redirects users from legitimate websites to fraudulent ones by altering DNS settings, poisoning DNS caches, or exploiting vulnerabilities. Once on a fake site, unsuspecting users often enter sensitive information, believing they’re using a legitimate service.

Botnets

Botnets are networks of internet-connected devices infected with malware and controlled by attackers without the owners’ knowledge. Hackers use various tactics to compromise devices, turning them into “bots” to perform coordinated malicious activities like launching DDoS attacks, distributing malware, spamming, or stealing sensitive data.

Rogue access points

Rogue access points are unauthorized wireless access points installed on a secure network without explicit authorization from the network administrator, either by a well-meaning employee or a malicious attacker. These physical devices, typically wireless routers or similar hardware, create unauthorized wireless entry points into the network or establish unauthorized Wi-Fi networks that may bring about a data breach.

Wi-Fi eavesdropping

Wi-Fi eavesdropping is a cyberattack where criminals intercept unencrypted data transmitted over wireless networks. They do so to intercept sensitive data such as login credentials, financial details, or private communications, especially on unsecured or public Wi-Fi networks.

Physical and device-based threats

Malicious actors don’t always target the software — they often aim to compromise devices themselves to access sensitive data stored within.

SIM swapping

SIM swapping is a type of account takeover fraud where attackers trick or bribe mobile carriers into transferring your phone number to a SIM card under their control. This way they can bypass two-factor authentication, intercept calls and texts, and gain access to sensitive accounts or personal information.

Mobile device breaches

Attackers may exploit software vulnerabilities in mobile devices to access them remotely by leveraging weaknesses in operating systems, apps, or third-party software. Poor device security, such as failing to enable multi-factor authentication, significantly helps attackers by making it easier to bypass authentication mechanisms and maintain unauthorized access.

Physical theft

Malicious actors may steal laptops, smartphones, and other portable devices that they later break into, which can result in a data breach.

Tailgating

Tailgating is simply following after an authorized employee into restricted areas without proper verification.

Shoulder surfing

Shoulder surfing is a technique where an attacker observes someone’s screen or keyboard from a close distance to steal sensitive information, like passwords or PINs. They typically do so in public places, such as cafes or airports. You should always take care to protect your screen from prying eyes.

Dumpster diving

Dumpster diving simply means going through someone’s trash in hopes of finding discarded documents or items that contain valuable information, such as bank statements or personal details.

Web application attacks

Another way for attackers to get access to an organization’s IT ecosystem is to try exploiting the vulnerabilities and weaknesses in web applications.

Cross-site scripting (XSS)

Hackers sometimes inject malicious scripts into trusted websites — this is called cross-site scripting (XSS). By using XSS, attackers are able to execute the script in their victim’s browser and steal cookies, session tokens, or sensitive data from their victim’s computer.

Cross-site request forgery (CSRF)

In cross-site request forgery, an attacker tricks you into executing unauthorized actions on a website where you are authenticated, often through a malicious link or script. This allows attackers to change account settings, transfer funds, or carry out other unintended operations without your knowledge.

Formjacking

Formjacking occurs when cybercriminals inject malicious JavaScript code into a website, taking over the functionality of its form pages to collect sensitive user information. Attackers intercept data such as credit card details entered by users in real time, often without the website or its visitors realizing the breach.

Drive-by downloads

A drive-by download is an unintentional download of malicious code to your computer. These downloads can happen when you visit compromised or malicious websites. Attackers exploit vulnerabilities in browsers, plugins, or operating systems to install malware, which can steal data or create backdoors for future attacks.

Exploit kits

Exploit kits are toolkits that attackers use to scan for and exploit vulnerabilities in software or systems so they can distribute malware or ransomware. These kits automate the process of identifying weaknesses, making it easier for cybercriminals to launch large-scale attacks against unpatched or outdated systems.

Buffer overflow attacks

In a buffer overflow attack, cybercriminals exploit buffer overflow, a software coding error, by sending more data to a memory buffer than it can handle, which causes excess data to overwrite adjacent memory. This allows attackers to execute malicious code, steal data, and gain unauthorized access to corporate systems.

Preventative measures and best practices

The onslaught of ways that attackers may breach your organization’s data security may seem overwhelming. However, a steady and proactive approach to security practices can strengthen your defenses against potential data breaches.

Network security

To take your corporate network security — and data protection — to the next level, you should implement a multi-layered approach that includes the use of firewalls, IDS, VPNs, and threat management solutions.

Firewalls create a barrier between trusted internal networks and untrusted external networks, blocking unauthorized traffic and filtering malicious data. If someone manages to bypass the firewalls, an IDS (intrusion detection system) can detect unusual activity and provide real-time alerts, enabling you to mitigate the threat promptly.

A VPN (virtual private network) secures data in transit, ensuring that remote workers and branch offices connect to the corporate network through encrypted channels to prevent eavesdropping and unauthorized access.

To top off your network security effort, start using a threat exposure management platform like NordStellar. It’s an advanced solution that automatically cross-references credentials found on the deep and dark web with your employee, customer, and partner accounts. If NordStellar’s Data Breach Monitoring solution finds any leaked credentials, it notifies you instantly, giving you the chance to take action to secure your accounts and resources.

Encryption

To protect sensitive corporate information, you should prioritize encryption by adopting data encryption in transit and at rest, as well as SSL/TLS protocols.

We advise encrypting your stored data on servers, databases, and devices to prevent a potential security breach, even if someone steals or compromises your data. You should also use encryption to secure data in transit between systems to prevent attackers from intercepting it during transmission over the internet or private networks.

Make sure to implement SSL/TLS protocols to secure web communications. This will create encrypted connections between users and websites and protect sensitive information like login credentials and payment details from potential breaches.

Access controls

Curbing data breaches also involves controlling who can access sensitive information and systems. Role-based access control is an effective approach that allows you to assign permissions based on an employee’s job responsibilities. It’s safest to only let individuals have access to the tools and data necessary for their role.

Equally important is the principle of least privilege, which means granting users the minimum level of access required to perform their tasks. By restricting permissions to only what’s essential, you can significantly reduce the attack surface, making it harder for cybercriminals to exploit compromised data.

Data minimization

It’s recommended to practice data minimization in any business. By collecting only the information necessary for your business operations, you avoid excess data — unnecessary or redundant information stored in your systems — that could become an attractive target for hackers.

A lean and secure data management system also includes regular purging of outdated or redundant data to reduce storage demands and limit the impact of a potential security breach.

Physical security

Ensure physical infrastructure is secure by securing server rooms with controlled access measures like keycards or biometric locks. Complement this with surveillance systems to monitor critical areas. A surveillance system may deter intrusions and provide evidence in case of a security breach.

Regular software updates

Protect your systems by regularly updating software, operating systems, and applications to patch vulnerabilities that attackers could exploit. Enable automatic updates where possible to ensure your systems always run the latest, most secure versions.

Strong password policies

Enforce strong password policies by requiring your employees to use complex, unique passwords and regular updates to protect against identity theft and security breaches. Encourage your employees to use password managers to securely store and manage their credentials.

Implementing multi-factor authentication

Multi-factor authentication (MFA) adds an extra layer of security and protection against identity theft because users must verify their identity through multiple methods before they can gain access to their accounts or company resources. MFA makes it harder for attackers to exploit compromised passwords alone.

Data backup and recovery plans

Make sure you regularly back up your data and have a set recovery plan if a data breach occurs. Storing your critical information securely is especially important in case of a cyberattack, hardware failure, or system disruption.

Regular security audits

Conduct regular security audits to identify vulnerabilities, assess the effectiveness of your cybersecurity measures, and ensure compliance with industry standards. These audits will help you stay proactive in addressing potential threats before they become serious issues.

Employee training and awareness

The more your employees know about data breaches and security practices, the better you are equipped to both protect your business from security breaches and respond to them in a timely manner. Regular employee training is a must to avoid data breaches due to human error.