Verbose Error Messages
Overview of verbose error message vulnerabilities, their risks, and mitigations. This entry highlights how excessive error details can disclose sensitive information.
Description
Verbose error messages occur when applications expose detailed diagnostic information to end users. These error responses may include stack traces, database queries, file paths, configuration values, or even secrets such as API keys and credentials.
While error messages are essential for debugging, exposing them in production systems creates an information disclosure vulnerability. Attackers can leverage these insights to enumerate technologies, map internal systems, and pinpoint weaknesses that may otherwise remain hidden.
For example:
- A SQL error message may reveal the type and version of the database in use.
- A stack trace may disclose file paths or class names, giving attackers a blueprint of the backend logic.
- A misconfigured API might expose internal identifiers or even partial credentials.
Why This Matters
Verbose error messages often seem harmless, but they can give attackers just enough context to craft precise and devastating exploits.
Remediation
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Use generic error messages in production Ensure applications display non-specific, user-friendly messages such as “An error occurred. Please try again later.”
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Log detailed errors securely Capture full stack traces, queries, and debug details in server-side logs with restricted access, not in user-facing responses.
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Separate environments Use different error handling policies for development (verbose logging) and production (suppressed output).
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Centralized error handling Implement global error handling mechanisms that enforce consistent, sanitized messages across the entire application.
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Sanitize user input Prevent malformed input from triggering verbose errors by validating and sanitizing input at all entry points.
References
MITRE ATT&CK Techniques
- T1087 - Account Discovery - Username enumeration via errors
- T1046 - Network Service Discovery - Service fingerprinting
- T1592.002 - Gather Victim Host Information: Software - Version disclosure
Common Weakness Enumeration
- CWE-209 - Generation of Error Message Containing Sensitive Information - Primary weakness
- CWE-497 - Exposure of Sensitive System Information to an Unauthorized Control Sphere - System information leakage
Security Resources
- OWASP: Improper Error Handling - Best practices
Next Steps
Verbose error messages are a common form of information disclosure. From here, you may want to explore related vulnerabilities such as:
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