What is Sensitive Data? 5 Top Strategies For Securing It

Understanding Sensitive Data in the Cybersecurity Context

Sensitive data is any information that if exposed, altered, or destroyed without authorization could result in harm. That harm may affect individuals, businesses, or governments. The National Institute of Standards and Technology (NIST) specifically outlines sensitive data as information that, if improperly disclosed, accessed, modified, or lost, could harm the national interest or federal programs.

In 2025, the risks tied to sensitive data exposure are rising sharply. As operations scale, attack methods evolve, and third-party risks soar, organizations must treat sensitive data not just as a security concern but as a strategic asset.

These exposures are not theoretical—they are operational, legal, and reputational threats. More than one in three breaches now originate from third parties, according to SecurityScorecard data from 2025.

• Breaches in the healthcare, pharmaceuticals, and biotechnology, which touch a plethora of sensitive data such as Protected Health Information (PHI), have the highest overall volume of breaches and third-party breaches of any sector.
• Government, defense, and aerospace are a close second for overall breach volume, SecurityScorecard’s research shows.
• Financial Services, Insurance, and Real Estate came in third for overall breach volume.

What Qualifies as Sensitive Data?

Cybersecurity and compliance teams must first classify and map their data before they can defend it. Sensitive data includes:

1. Personally Identifiable Information (PII)

Personally Identifiable Information (PII) includes names, Social Security numbers, phone numbers, and email addresses. PII is generally protected under regulations such as the European Union’s GDPR and the California Consumer Privacy Act (CCPA).

2. Protected Health Information (PHI)

Medical records, insurance data, and biometric identifiers fall under PHI. In the U.S., PHI is regulated by the Health Insurance Portability and Accountability Act (HIPAA).

3. Financial Information

Bank account details, credit card numbers, tax documentation, and payment records. This data is governed by frameworks like the Payment Card Industry Data Security Standard (PCI DSS).

4. Credentials and Authentication Data

Usernames, passwords, multi-factor authentication (MFA) tokens, and API keys. These are prime targets for attackers.

5. Proprietary Business Data

Trade secrets, source code, product plans, and internal communications. Unauthorized disclosure may lead to financial loss or competitive disadvantage.

Strategy 1: Classify and Inventory Your Data

You can’t protect what you don’t know exists. Many breaches can stem from unknown, untracked, or misclassified data.

Recommended actions:

• Use automated tools to discover sensitive data across endpoints, cloud storage, and SaaS apps
• Tag data by sensitivity level (such as public, internal, confidential, restricted, biometric, and sensitive)
• Maintain a real-time, continuously updated data inventory.

Some compliance frameworks are updating in 2025 to encourage better data inventory practices. HIPAA, for instance, is moving to require healthcare organizations to identify their technology assets and track the movement of PHI throughout their environment.

Strategy 2: Enforce Access Controls

Over-permissioned accounts are a major source of data leaks. Many breaches begin with credential theft or insider misuse as well:

• Credential abuse remains the most common vector for attacks, according to Verizon’s Data Breach Investigations Report of 2025, to which SecurityScorecard was a contributing organization.
• Insider privilege misuse breaches are on the rise, according to Verizon’s 2025 data.

Best practices:

• Enforce least-privilege access
• Use Role-Based Access Control (RBAC)
• Require multi-factor authentication (MFA) for all privileged accounts
• Audit access regularly and decommission unused accounts

Strategy 3: Encrypt Sensitive Data Everywhere

Encryption remains one of the most effective safeguards against prying eyes, yet many organizations fail to apply it consistently.

What to encrypt:

• Data at rest: On servers, databases, backups
• Data in transit: Emails, file transfers

Cryptographic standards to consider::

• Use AES-256 for storage
• Enforce TLS 1.2 or higher for transmission
• Deprecate outdated algorithms, such as SHA-1 or 3DES

SecurityScorecard continuously scans for expired or weak TLS certificates across your digital footprint. These are often overlooked entry points for attackers exploiting misconfigured third-party environments.

Strategy 4: Monitor and Respond in Real Time

Point-in-time audits no longer suffice. Data risk changes daily, and your organization needs systems that detect threats as they emerge to move you from reactive to proactive cybersecurity operations.

Key capabilities:

• Detect unencrypted data moving across insecure channels
• Identify publicly exposed storage (such as exposed S3 buckets)
• Monitor dark web forums and ransomware leak sites for stolen data
• Track exploits in commonly used file transfer software (such as Cleo CVEs in 2024)

SecurityScorecard’s Supply Chain Detection and Response (SCDR) solution alerts organizations to leaked credentials, unpatched systems, and emerging threats in their third-party ecosystem.

Strategy 5: Train the Human Layer

People remain a primary vector for data leaks. Humans account for approximately 60% of breaches, according to Verizon’s Data Breach Investigations Report of 2025. Training and governance are as important as technical controls.

Recommendations:

• Run mandatory security awareness training
• Simulate phishing and data exfiltration attacks
• Enforce policies on data sharing, storage, and disposal
• Include sensitive data scenarios in incident response plans

Data governance must span departments, from legal and HR to engineering and procurement.

The Third-Party Blind Spot

Many organizations outsource functions to service providers, contractors, and third parties, yet fail to validate how vendors handle sensitive data.

Findings from SecurityScorecard’s 2025 breach report:

• 41.4% of ransomware attacks, which can allow hackers to exfiltrate sensitive data, start with third-parties
• Healthcare, defense, and finance, each of which handle a massive amount of sensitive data, are among the most impacted
• File transfer software and cloud tools are key enablers

To reduce risk:

• Require encryption of third-party data at rest and in transit
• Include specific data protection clauses in vendor contracts
• Monitor third-party data handling continuously using SecurityScorecard solutions

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