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Home   >Best Practices

Top Email Risks When Sending Sensitive Files to External Stakeholders

January 23, 2024
What are the top risks experienced when sending sensitive files to external stakeholders by email?
The top risks incurred by orgs fall into these four main categories: insider risks, active threats, technical failures, and supply chain risks. It's worth noting that risks can arise from behavaiors both unintentional and intentional.

It is a truth universally acknowledged that email remains the default tool for external collaboration despite its risks.  Across industries and sectors, teams frequently turn to email when working with external stakeholders, drawn by its ubiquity, ease of use, and broad acceptance. 

Email's role extends beyond just exchanging messages; it has also become a common medium for transmitting sensitive files. This dependence on email is rooted in its ability to facilitate direct, swift communication, enabling organizations to share documents and make decisions efficiently. It serves as a bridge between organizations with different processes, procedures, and technological infrastructures. For example, during contract negotiations between a company and an external supplier, email are used to exchange contract documents.

However, the reality of using email to send sensitive files is replete with risks. This article is dedicated to exploring these risks. We delve into the security challenges of relying on email for sensitive file transmission in external collaborations, examining the implications for all parties involved. 

How threats, vulnerabilities, and risks intersect

For many people, cybersecurity concepts like threats, vulnerabilities, and risks merge in their head. We talk about the threat of hacking, or systems that are vulnerable to intrusion, or the risk of loss from a data breach.  These things all sound the same, but they are not the same thing. To better understand the risks created by sending secure files by email, we also need to understand concepts like threats and vulnerabilities. 

Before we go on, let’s quickly define those terms. 

  • Threats: A threat is any potential danger that can exploit a vulnerability. In the context of email, this could be hackers trying to access email servers or phishing attacks aimed at tricking users into revealing sensitive information.
  • Vulnerabilities: Vulnerabilities are weaknesses or flaws that can be exploited by a threat. In email systems, these could be outdated software, lack of encryption, or poor password policies.
  • Risks: These are the potential negative consequences that arise when a threat exploits a vulnerability. In the case of email, this could mean data breaches, loss of sensitive information, or compliance violations.

One common view of threats, vulnerabilities, and risks is the following view.  In essence, threats combine with vulnerabilities to create risks. In the terms of 

How threats combine with vulerabilities to create risks

This is the mental model we’ll use in the next section as we consider the risks created by sending sensitive files by email. 

What are sensitive files?

Colloquially, “sensitive files” are files or documents that include data or content that you’d rather not see widely distributed.  Because of the recent focus on personal privacy regulations such as the European Union’s General Data Protection Regulation (GDPR), California Consumer Privacy Act (CCPA),  many organizations have assumed that sensitive files only pertain to documents, files, or systems that might contain “special categories of personal data.” 

That’s far too limiting, especially when we look through the lens of external collaboration. From this point of view, sensitivity is much more expansive, it goes beyond just personal data to include any documents or files that either party would prefer to keep confidential. We can see this by using the standard classification scheme found in ISO 27001:

Public: Information that is non-confidential and can be freely distributed. By definition, no sensitive files should exist here.

Internal: Data intended for internal use, with access controlled by management.

Example of sensitive files:

  • Drafts and discussions on contracts or agreements with external parties.
  • Confidential assessments or reports on partnerships.
  • Strategy documents and negotiation tactics for collaborations.
  • NDAs and internal legal documents related to external collaborations.
  • Internal communications about collaboration terms and conditions.

Customer Data: Information from customers, handled with high confidentiality and integrity.

Example of sensitive files:

  • Contracts and service agreements with third-party involvement.
  • Personal data of customers shared under external agreements.
  • Correspondence regarding third-party collaborations.
  • Customer feedback or complaints about external partners.
  • Data involving customer information shared with external entities.

Company Data: Operational data crucial for the business, requiring strict confidentiality.

Examples of sensitive files:

  • Financial reports and business strategies shared with external parties.
  • Confidential R&D information disclosed to partners.
  • Policies and compliance documents shared with regulators or auditors.
  • Employee data shared with external HR services or consultants.

Notice that with ISO 27001’s more party-driven categorization, what might not appear sensitive to your party may be very sensitive to the other (i.e., all the material in the customer data classification) and vice versa. In fact, mishandling these files can lead to breaches, legal repercussions, and loss of trust–hardly what you want when trying to collaborate with an external stakeholder.  This wide spread of sensitive files (yours, mine, and ours) underscores the importance of thinking beyond your security and confidentiality requirements, and considering your external stakeholder’s requirements. And protecting these files requires robust security measures like encryption, access control, and secure collaboration platforms that ensure confidentiality while maintaining efficiency.

The Risks of Sending Sensitive Files By Email

When we think about the risks of email, it's common to focus on active threats — the hacker breaking into your email server, phishing attacks, or emails being intercepted by a malicious party. However, the categories of risk extend far beyond those dramatic scenarios. Understanding these risks is crucial for organizations to protect sensitive information effectively and maintain trust with external stakeholders.

Our overview covers key categories of risk observed in email communication. Note that while environmental factors (e.g., natural disasters) and regulatory issues are also important, they are not included in this overview to focus on the most direct risks related to email communication.

The top categories of risks experienced when sending sensitive files by email

Insider Risks

Often the most common source of security incidents, these risks arise from within the organization and can be both unintentional and intentional. It’s worth noting that unintentional errors can be just as damaging as malicious efforts by insiders.  Insider risks include, but are not limited include user errors (like sending emails to the wrong recipient), accidental exposure of data due to lack of awareness, and deliberate actions by malicious insiders.

Wrong Recipient: A common error where emails are accidentally sent to the wrong person.

  • Threat: Internal stakeholder/employee errors
  • Vulnerability: Putting the wrong person on the To, CC, or BCC lines
  • Risk: Misdirected Sensitive Information
  • Business Impact: Potential privacy breaches, reputational damage, and inadvertent data disclosure

Wrong Attachments: Occurs when an email is sent to the right person, but with the wrong attachments, potentially exposing sensitive data.

  • Threat: Internal stakeholder/employee errors
  • Vulnerability: Attaching and sending incorrect files
  • Risk: Unintended Information Exposure
  • Business Impact: Accidental leakage of confidential or sensitive data, leading to trust and credibility issues

Wrong Attachment Versions: Involves distributing a file that is outdated or not meant for sharing, leading to misinformation.

  • Threat: Internal stakeholder/employee errors
  • Vulnerability: Distributing outdated or unreviewed versions of files
  • Risk: Distribution of Outdated Versions or Inaccurate Information
  • Business Impact: Miscommunication and potential operational errors due to reliance on incorrect information

Information Overload and Mismanagement: Risks created due to issues in managing high volumes of email effectively.

  • Threat: Overwhelming Volume of Email
  • Vulnerability: Inability to effectively manage and prioritize a high volume of email communications
  • Risk: Overlooked Critical Information, Operational Delays
  • Business Impact: Reduced productivity, increased risk of missing important or urgent communications, decision-making based on incomplete information

Employee Burnout and Productivity Loss: Negative impact of excessive email usage on employee well-being.

  • Threat: Excessive Email Demands, Continuous Connectivity Expectations 
  • Vulnerability: Culture of constant connectivity and expectation of immediate response, communication across multiple channels (email + Slack/Teams/SMS, etc)
  • Risk: Employee burnout, reduced job satisfaction and efficiency
  • Business Impact: Lower overall productivity, increased employee turnover, higher rates of absenteeism

Lack of Training: Risks arising from employees not being adequately trained on email security protocols.

  • Threat: Lack of Awareness
  • Vulnerability: Insufficient employee training and awareness about email security
  • Risk: Accidental Data Breaches
  • Business Impact: Loss of sensitive data, potential legal issues, and damage to reputation

Malicious Insiders: Deliberate actions by insiders to leak sensitive information for personal gain or to harm the organization.

  • Threat: Malicious Insiders
  • Vulnerability: Inadequate internal security measures and access controls
  • Risk: Intentional Leakage of Confidential Information
  • Business Impact: Significant financial loss, legal consequences, and severe reputational harm

Active Threats

This category includes deliberate, external efforts to compromise email security. It encompasses hackers targeting email servers, phishing and social engineering schemes to deceive users, interception of emails, as well as sophisticated cyberattacks and espionage (APTs). These threats aim to steal data, disrupt communication, or gain unauthorized access.

Phishing/Social Engineering: Deceptive practices aimed at tricking users into divulging sensitive information or credentials.

  • Threat: External Actors (Phishers, Scammers)
  • Vulnerability: User susceptibility to deception
  • Risk: Disclosure of Sensitive Information
  • Business Impact: Data theft, potential financial fraud, and damage to user trust

Malware/Ransomware: Malicious software spread via email, designed to damage systems or hold data for ransom.

  • Threat: Cybercriminals distributing harmful software
  • Vulnerability: Unsecured email attachments, lack of malware protection
  • Risk: System Infection and Compromise, destruction of sensitive files
  • Business Impact: Significant operational disruption, data loss, financial costs from ransom payments

Hacking: Unauthorized access attempts to breach email systems and gain access to sensitive data.

  • Threat: Cybercriminals, Hackers
  • Vulnerability: Weak or compromised email security systems
  • Risk: Data Breaches and Unauthorized Access, exfiltration of sensitive data and attachments
  • Business Impact: Loss of critical data, operational disruption, and potential legal repercussions

Unauthorized Access: Intrusions where unauthorized individuals gain access to email accounts or servers.

  • Threat: Hackers, Disgruntled Employees
  • Vulnerability: Inadequate access control and authentication measures
  • Risk: Unauthorized Access to Confidential Data
  • Business Impact: Breach of privacy, loss of sensitive data, and compliance issues

Email Interception: Unauthorized interception and reading of email communications during transmission.

  • Threat: Hackers, Surveillance Agencies
  • Vulnerability: Unencrypted email transmission, network vulnerabilities
  • Risk: Interception of Sensitive Communications
  • Business Impact: Loss of confidentiality, potential exposure of strategic or personal data

Technical Failures 

Technical issues such as hardware and software failures, outdated systems with unpatched security flaws, and inadequate network security can lead to significant risks, including data loss and compromised email integrity.

Hardware/Software Failures: Failures or malfunctions in the hardware or software supporting email systems.

  • Threat: System Breakdowns
  • Vulnerability: Lack of redundancy and backup systems
  • Risk: Data Loss and System Downtime
  • Business Impact: Disruption of operations, potential loss of data, and costs associated with data recovery

Outdated Software: Use of email software or systems that are not regularly updated or patched.

  • Threat: Exploitation of Known Vulnerabilities
  • Vulnerability: Unpatched security flaws in email software
  • Risk: Increased Vulnerability to Cyber Attacks
  • Business Impact: Higher risk of security breaches and data compromise due to known vulnerabilities

Excessive Email and Attachment Retention:  Storing large volumes of emails and attachments in inboxes for extended periods.

  • Threat: Data Breach Risk Amplification
  • Vulnerability: Accumulation of sensitive information in accessible locations (email inboxes)
  • Risk: Increased Exposure in the Event of a Breach
  • Business Impact: In the event of unauthorized access, a larger repository of sensitive data becomes available to attackers, potentially leading to significant data breaches.

Network Security Weaknesses: Inadequate security measures for the network infrastructure supporting email communication.

  • Threat: Network Intrusions
  • Vulnerability: Unsecured or poorly configured network connections
  • Risk: Unauthorized Access and Data Interception
  • Business Impact: Compromise of email integrity and confidentiality, potential exposure of sensitive communications

Supply Chain Risks

Risks associated with third-party services and vendors, including vulnerabilities in third-party email services and integration issues with other business applications, can affect the security of email communications.

Vendor Compliance and Regulation Risks: Risks arising from vendors not adhering to legal and regulatory standards.

  • Threat: Non-compliance with regulations like GDPR or HIPAA.
  • Vulnerability: Dependence on vendors for handling sensitive data.
  • Risk: Regulatory non-compliance.
  • Business Impact: Legal penalties, fines, reputational damage.

Third-Party Vulnerabilities: Security weaknesses in third-party services, like email hosting or cloud storage, used by organizations (includes forth-party or subcontractor risks).  

  • Threat: Breaches in Third-Party Services
  • Vulnerability: Dependence on external email and data storage services
  • Risk: Compromised Data Security
  • Business Impact: Exposure of sensitive information, reliance on external entities for data security

 Supply Chain Interruption Risks: Risks of disruptions in the supply chain affecting the availability or integrity of critical email services or other operations.

  • Threat: Operational disruptions due to third-party service failures.
  • Vulnerability: Reliance on essential third-party services.
  • Risk: Interruptions in email service leading to communication breakdowns.
  • Business Impact: Operational delays, decision-making disruptions, and potential financial losses.

Reputational Risks: Risks stemming from association with vendors involved in unethical practices or data breaches.

  • Threat: Negative public perception due to vendors' actions.
  • Vulnerability: Partnerships with entities having varied standards.
  • Risk: Damage to public image and trust.
  • Business Impact: Loss of customer trust, potential business loss.

Ways to Reduce Risks When Sending Sensitive Files by Email

To effectively mitigate the risks associated with sending sensitive files by email, traditional methods like encryption, using secure email gateways, implementing strong password policies, and regular cybersecurity training for employees are essential. These practices form the backbone of a secure email communication strategy, ensuring basic safeguards against many of the risks outlined earlier.

  • Encryption: Encrypting emails ensures that even if intercepted, the contents remain unreadable to unauthorized parties.
  • Secure Email Gateways: These act as filters to block malicious emails and prevent data leakage.
  • Strong Password Policies: Robust passwords, coupled with multi-factor authentication, protect email accounts from unauthorized access.
  • Cybersecurity Training: Regular training sessions help employees recognize and respond appropriately to security threats like phishing.

However, as our understanding of collaboration tools evolves, a more fundamental approach to risk reduction emerges. One of the most effective strategies to mitigate these risks is, quite simply, to reduce reliance on email for sending sensitive files.

Transitioning to External Collaboration Platforms as a Risk Avoidance Strategy

In today's digital landscape, numerous external collaboration platforms offer robust security features tailored for sharing sensitive information. These platforms often provide better control over who can access the information, audit trails, the ability to retract access, and secure environments for collaborative work without the need to send files back and forth via email.

For instance, platforms like TakeTurns offer sophisticated security measures and collaboration features that email lacks. They allow real-time collaboration, version control, secure file sharing, and integration with other tools, significantly reducing the risks associated with email communication.

By transitioning to such platforms, organizations can not only enhance the security of sensitive information but also improve collaboration efficiency. This shift represents not just a technological change but a strategic move towards a more integrated, secure, and efficient way of handling external collaborations.

TakeTurns can reduce your risk when collaborating on sensitive files with external stakholders.


While emails remain a staple in business communication, their role in sharing sensitive files should be re-evaluated in light of the inherent risks involved. By combining traditional email security practices with the adoption of external collaboration platforms, organizations can significantly reduce the risk of data breaches and other security incidents. This dual approach ensures not only the protection of sensitive information but also fosters a more collaborative, productive, and secure working environment.


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