The Hidden Risk: Leaked Employee Emails

Not long ago, most people assumed cybercriminals only went after big corporations—companies with deep pockets and the resources to absorb the fallout. But we know better these days–regardless of size or industry, any company can be made a breach target. Data breaches are an imminent threat to all who use the internet.

Criminals may target a company because they lack sufficient security or because they want to steal valuable information—like customer data or internal credentials. In fact, Verizon’s 2023 Data Breach Investigations Report found that 74% of breaches involved the human element, including social engineering and misuse, which often begin with poor security hygiene or leaked data from earlier attacks. 

How a cyber criminal chooses their target depends on their goals, but one of the most common ways they make such a determination is by utilizing information stolen in previously successful data breaches.

Bad actors can launch a data breach in many ways. They might trick an employee into sharing account details by impersonating someone with the correct authority, attack a company’s systems directly through brute-force events, or wiggle their way into a system using stolen information. Modern cybersecurity strategies are created with these potentials, and email security plans are among the most vital.

Employee email leaks can impact entire corporations, making data breach prevention a critical priority resulting in financial and reputational losses. Understanding how these leaks happen is just the first half of the equation. The other half? Grappling with what they actually cost—financially, operationally, and legally. Data breaches are part of our daily lives, but we can reduce their impact with the proper precautions.

The Rising Threat of Email Leaks in Data Breaches

These days, emails are one of the most relied-upon communication resources—and also one of the most common entry points for cyberattacks, making phishing training an essential layer of defense. They can contain sensitive internal data about users and a company’s systems while offering a reliable method of communication between employees and departments. An employee’s email account is uniquely tailored to their company’s needs, so when these emails are leaked or breached, the email can also act as a flexible door for bad actors.

However, cybercriminals are only part of the threat environment—internal actors and human error often pose just as much risk, which is why many experts advocate a 'trust but verify' approach to internal security. Employees’ actions are equally significant, at least in terms of cybersecurity defenses. Improperly trained or careless employees can expose a company (as well as its clients and vendors) to further cyber attacks.

Employees are prime targets for credential stuffing, phishing attacks, and social engineering plots. According to IBM’s Cost of a Data Breach Report, phishing was the most common initial attack vector in breaches, leading to average costs of $4.91 million. Attackers exploit email to manipulate trust, steal credentials, or gain a foothold inside systems, especially when phishing training is inconsistent or absent. Cybersecurity experts suggest that nearly a quarter of all cyberattacks begin with a suspicious email. If an employee becomes fatigued or careless, the chances that they will accidentally fall victim to these potential attacks increase dramatically.

An organization’s vulnerabilities only increase when an employee leaves their position. An estimated 12% of an ousted workforce takes valuable information with them—a classic example of an intentional insider threat, including account details like passwords, system knowledge like network structures, and contact details for everyone in the company. Consequently, unless a company’s technology experts are on top of all the movements of an employee network, there could be increased threats long after an employee stops coming to work.

The Consequences of Email Leaks for Businesses

One of the most valuable pieces of information employees take with them when they leave is company emails. These are often the same emails leaked following successful data breaches. When an organization's emails are leaked, the most common consequences are financial losses, reputational damage, operational issues, and regulatory fines–it's up to companies to learn when and how to prioritize their defenses accordingly.

Financial Losses

Although cybercriminals' goals are mysterious, leaking email addresses can devastate a business’s financials. If the attack includes ransomware, a victimized company may feel forced to meet a threat’s demands or expose sensitive data.

These same victims can also become targets for fraudulent activities, with cybercriminals using internal email accounts to collect and redirect money to private accounts. A company’s financial losses don’t stop with the immediate loss of funds through malware or fraud; they can lose further money through subsequent investigations and regulatory fines.

Reputational Damage

Businesses also suffer reputational damage following a leak. A company with a history of data breaches will likely lose public customer and vendor trust, brand authority, and information security credibility.

Such losses may not seem essential to businesses, but it quickly becomes apparent that the loss of public trust means a company’s future. Historical data breaches, like those associated with social media platforms, are a significant reason for the ultimate downfall of those previously successful groups. 

Operational Disruptions

Operational hiccups on the production floor or in the supply chain might seem minor—but this attitude enables continuous losses for victimized companies. An operational disruption may refer to a loss of a few days worth of work, but in that time, the business is repeatedly suffering.

For example, consider any downtime due to a cyber attack. Downtime results in lost production, revenue, time, and repeated disruptions can impact a company’s reputational stance, too. Even worse, these issues can contribute to a compromised business continuity plan, throwing a previously organized system into chaos.

Regulatory Penalties

In a land of businesses, regulators are the lawmakers. Compliance risks are a significant reason for closing an organization’s doors, so when a cyber attack targets a company outside those guidelines, they are likely doomed to the same fate.

Many state and federal regulations, including the GDPR, CCPA, and HIPAA, influence a cyber breach’s legal ramifications. Failure to comply with any of them can result in substantial financial and reputational costs. Customers may consider the business unprofessional, while vendors may consider such businesses a liability; either way, the victim of a cyberattack continues to suffer losses.

How to Monitor and Detect Leaked Emails 

Organizations aren’t alone in the fight against cyber attacks; they can help defend themselves and their constituents by enabling monitoring services like real-time email monitoring and domain-based surveillance.

Dark Web and Breach Monitoring Services

When a company’s network is compromised, criminals can harvest all the data held within and sell it to the highest bidder (unless they have additional security measures to stop it from happening). The dark web is a highly active environment, allowing criminals to trade and purchase stolen information, often for under $50 a file.

Consequently, businesses must consider their profiles appearing in a dark marketplace. Monitoring dark web activity is one additional way organizations can strengthen their defenses against data misuse and account compromise (and individuals). Organizations can also implement break monitoring services. These can alert experts if a device is active, helping to stop malicious actors from gaining system access physically. 

Real-Time Email Security Monitoring

No one can manually review all email accounts and activity. Businesses face enough daily challenges without diverting valuable staff resources to manually monitor potential threats. As a result, many cyber defense experts support using artificial intelligence (AI) tools. AI threat detection can be vital in assessing a system's current status and the potential outcomes of a successful attack. Advanced AI systems can “understand” an attacker’s path, creating a real-time threat assessment and launching isolating initiatives to restrict the actor to a single network area.

Domain-Based Monitoring

Expert systems can monitor emails at every stage of the process. Whether they are written, sent, received, or opened, they can trigger system alerts. Consequently, companies with multiple layers of employees and more than one domain entrance can create checkpoints to monitor and assess an email before it reaches an employee.

Monitoring emails at the corporate domain level can prevent many threats from entering a system, where an employee is restricted at every level not associated with their role. Moreover, some organizations are implementing even stricter defenses, such as zero-trust architectures, which force employees to verify their identities multiple times.

Best Practices to Protect Employee Emails 

There are numerous ways to protect employee emails from malicious characters, but how much impact they have in a cyber event depends on how the company prioritizes them. Most organizations will see a defense boost from implementing multi-factor identification processes, employee staff training, and regular security audits.

Implementing Strong Authentication Mechanisms

Multi-factor authentication is essential for every account, reinforcing a 'trust but verify' mindset that helps prevent unauthorized access even when credentials are compromised, whether attached to a business or a personal interest. A few years ago, criminals ended the idea that two-factor authentication was good enough for security; some criminals can bypass two-factor processes with advanced technology designed explicitly for the task. Such attacks are primarily why the new standard has become “multi-factor” instead; two steps aren’t enough to stop a threat.

At the same time, the public has also been introduced to password managers. Password software like this is specifically designed to generate, collect, and maintain account details. That’s great in an era where every business wants employee and consumer accounts—but no one can remember their passwords.

Employee Cybersecurity Awareness Training

Of course, a business workforce is particularly endangered when it lacks training. When employees aren’t adequately trained, they lack the necessary knowledge to recognize a threat when it appears. An employee who hasn’t been taught the red flags of a scammer is more likely to fall for impersonations and urgent requests for information.

Phishing simulations are among the most beneficial phishing training programs that companies can implement to prepare their workforce. Phishing refers to a cybersecurity threat that attempts to collect information for later use, such as financial, account, or personal details. If employees are trained to recognize the signs of an attempted phishing message, they can notify experts to investigate its source.

Regular Security Audits and Access Controls

But even airtight defenses can fail. That’s why response matters just as much as prevention.

Companies that rely on networks to provide a service or to interact with clients know that regular testing of their online environment is essential. Regular penetration testing can also be valuable during these assessments because a network’s vulnerability status can change overnight. Regular testing of access points and potential issues can go far in identifying and stopping potential threats.

As mentioned above, some organizations are turning to zero-trust architectures to fortify their systems. However, a business does not need specialized infrastructure to build strong defenses. Implementing access controls of any form is an excellent way to keep most threats out, especially when combined with endpoint security solutions, especially in terms of endpoint security. These defenses operate like multi-factor authentication, but at an employee level.

For example, a low-level employee being restricted from accessing a manager's files or a manager being restricted from accessing an administrator's files. Either way, with these additional restrictions, threats cannot move very far without a lot of hard-to-get authorization details.

Incident Response Plan for Email Breaches

Of course, if the unthinkable does happen, having a well-thought-out incident response planning strategy in place can make all the difference in how the situation unfolds and what recovery looks like. Companies must consider building a breach response plan—better yet, incorporate incident response planning into the fabric of everyday operations, but automated account resets and notification alerts are also key in stopping and responding to malicious threats.

Establishing a Breach Response Protocol

Every company is nuanced; subsequently, their experts must determine the specific breach protocols that will protect them the best. However, in most cases, the process will look something like:

• It is vital to isolate the threat as soon as it is found or suspected. Disconnecting all networks, systems, and devices limits the access of a malicious actor.

• Restricting access to network entry and devices is also key, as many companies require at least some active accounts to continue work (albeit at a lower rate).

• Next, assessments of the compromised but isolated systems are necessary—a key step in any effective cybersecurity incident response.
• Investigations are another typical phase following a breach. Most companies without in-house experts must pay for a private investigator, but they are always beneficial.

Automated Account Revocation and Credential Resets

Resetting passwords and account credentials is a critical part of any breach protocol. Once a malicious actor is within a system, they could steal anything, including passwords; subsequently, those passwords could be used for further criminal activities, as is the case with credential stuffing attacks.

Companies often benefit most from launching all-employee credential change initiatives in these situations. Automated versions of these processes ensure that all employees make the change together, meaning better protection for every community member.

Notification and Mitigation Strategies

When a breach occurs, the company that is victimized must notify the impacted parties. The expectations are clear, whether this obligation is within 24 hours, as in Maine, or within 2 years, as in Texas. Organizations suffering from these attacks must notify those potentially impacted or face lawsuits at the public and federal levels.

Lastly, a corporation must also consider mitigating subsequent attacks as part of a broader data breach response strategy. Once cybercriminals successfully enter a network, they are more likely to attempt to attack it again. Understanding how they entered the first time can help prevent them from entering again.

Not only is the threat of leaked emails on the rise, but so are the consequences of those events.

Why This Threat Demands a Response

A company with a breached email account may suffer financial and reputational losses—a real-world reminder of the definition of a security breach and what’s at stake when sensitive data is exposed, production disruptions, and even further penalties from state and federal agencies.

Although cyber attacks are becoming increasingly frequent, consistent incident response planning remains one of the most effective ways to prepare for and limit their impact. There’s still time to implement defenses to slow them down. Employees have a critical role in defending such details—they can use strong multi-factor authentication processes to help limit the reach of a bad actor.

Further, businesses can protect themselves, their employees, and the public by establishing an incident response plan that utilizes a breach response protocol, automated credential resets, and proper mitigation strategies. Businesses that have yet to consider defending their employee emails are already at risk, but the window to act is still open. The companies that will come out ahead are the ones that treat employee email like the frontline it truly is.