CWE-211: Externally-Generated Error Message Containing Sensitive Information
Official CWE-211 CWE context with Glexia analysis, remediation guidance, related CVEs, and ATT&CK context.
Glexia's Take
CWE-211: Externally-Generated Error Message Containing Sensitive Information
Externally-Generated Error Message Containing Sensitive Information represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality: Read Application Data
Developer Pattern
CWE-211 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Confidence
high confidence from CWE-211, 4.20.
Official CWE Definition
CWE-211: Externally-Generated Error Message Containing Sensitive Information
The product performs an operation that triggers an external diagnostic or error message that is not directly generated or controlled by the product, such as an error generated by the programming language interpreter that a software application uses. The error can contain sensitive system information.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- The following servlet code does not catch runtime exceptions, meaning that if such an exception were to occur, the container may display potentially dangerous information (such as a full stack trace).
- In the following Java example the class InputFileRead enables an input file to be read using a FileReader object. In the constructor of this class a default input file path is set to some directory on the local file system and the method setInputFile must be called to set the name of the input file to be read in the default directory. The method readInputFile will create the FileReader object and will read the contents of the file. If the method setInputFile is not called prior to calling the method readInputFile then the File object will remain null when initializing the FileReader object. A Java RuntimeException will be raised, and an error message will be output to the user. However, the error message output to the user contains information regarding the default directory on the local file system. This information can be exploited and may lead to unauthorized access or use of the system. Any Java RuntimeExceptions that are handled should not expose sensitive information to the user.
Remediation
- System Configuration: Configure the application's environment in a way that prevents errors from being generated. For example, in PHP, disable display_errors.
- Implementation,Build and Compilation: Debugging information should not make its way into a production release.
- Implementation: Handle exceptions internally and do not display errors containing potentially sensitive information to a user. Create default error pages if necessary.
- Implementation: The best way to prevent this weakness during implementation is to avoid any bugs that could trigger the external error message. This typically happens when the program encounters fatal errors, such as a divide-by-zero. You will not always be able to control the use of error pages, and you might not be using a language that handles exceptions.
Detection
- Code review
- SAST
- DAST
- Focused regression tests
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.