Sensitive Data Exposure

Description

Sensitive Data Exposure occurs when an application inadvertently discloses confidential or personal information, such as passwords, credit card details, health records, or proprietary business data. This can happen due to improper encryption (or lack thereof), insecure data storage, or insufficient access controls. Attackers exploit these weaknesses to gain unauthorized access to data in transit (e.g., via unsecured HTTP connections) or data at rest (e.g., unencrypted databases, configuration files).

When sensitive data is exposed, the consequences may include identity theft, financial fraud, regulatory penalties, and harm to an organization's reputation. Common causes include failing to use HTTPS, storing passwords in plaintext, or using weak encryption algorithms.

Examples

Unencrypted Connections

If a website transmits login credentials over HTTP rather than HTTPS, an attacker can intercept the data using sniffing tools on the same network. The credentials are then exposed in plaintext.

Plaintext Password Storage

Some applications store user passwords directly in a database without hashing or encryption. If an attacker gains access to the database, they can read every user's password. This also compromises users who reuse passwords on multiple sites.

Sensitive Tokens in URLs or Logs

Applications sometimes include session tokens, API keys, or access tokens within URL parameters. These tokens can appear in server logs, browser history, or referrer headers, exposing them to unintended recipients.

Weak or Deprecated Cryptographic Algorithms

Even if data is encrypted, using older or broken algorithms (e.g., MD5, SHA1, RC4) leaves that data vulnerable to well-known attack methods. Attackers can potentially decrypt or forge data if algorithms lack sufficient cryptographic strength.

Remediation

  1. Use Strong Encryption (Transport Layer Security)

    • Always serve sensitive pages (login, account management) over HTTPS.
    • Prefer TLS 1.2 or higher with secure cipher suites to protect data in transit from eavesdropping and tampering.

  2. Encrypt Sensitive Data at Rest

    • Store passwords using salted, one-way hashing functions (e.g., bcrypt, Argon2, scrypt).
    • For other sensitive data (e.g., financial or healthcare records), use robust encryption methods (e.g., AES-256) with secure key management.

  3. Avoid Storing Tokens in Logs or URLs

    • Do not include session IDs, API keys, or other secrets in query parameters. Instead, place them in secure HTTP headers or request bodies.
    • Ensure sensitive data is either masked or omitted in application logs, especially if they might be accessed or shared.

  4. Regularly Update Cryptographic Measures

    • Decommission weak or deprecated algorithms and protocols (SSLv3, TLS 1.0, MD5, etc.).
    • Stay informed about emerging cryptographic vulnerabilities; patch or upgrade your systems promptly.

  5. Implement Strict Access Controls

    • Restrict database access to only authorized users and processes.
    • Apply the principle of least privilege to both your application code and infrastructure.