Description
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.
Potential Impact
Confidentiality
Read Application Data
Demonstrative Examples
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username = request.getParameter("username");
// May cause unchecked NullPointerException.
if (username.length() < 10) {...}
}public class InputFileRead {
private File readFile = null;private FileReader reader = null;private String inputFilePath = null;private final String DEFAULT_FILE_PATH = "c:\\somedirectory\\";
public InputFileRead() {inputFilePath = DEFAULT_FILE_PATH;}
public void setInputFile(String inputFile) {
/* Assume appropriate validation / encoding is used and privileges / permissions are preserved */
}
public void readInputFile() {
try {reader = new FileReader(readFile);...} catch (RuntimeException rex) {System.err.println("Error: Cannot open input file in the directory " + inputFilePath);System.err.println("Input file has not been set, call setInputFile method before calling readInputFile");
} catch (FileNotFoundException ex) {...}
}
}Mitigations & Prevention
Configure the application's environment in a way that prevents errors from being generated. For example, in PHP, disable display_errors.
Debugging information should not make its way into a production release.
Debugging information should not make its way into a production release.
Handle exceptions internally and do not display errors containing potentially sensitive information to a user. Create default error pages if necessary.
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.
Real-World CVE Examples
| CVE ID | Description |
|---|---|
| CVE-2004-1581 | chain: product does not protect against direct request of an include file, leading to resultant path disclosure when the include file does not successfully execute. |
| CVE-2004-1579 | Single "'" inserted into SQL query leads to invalid SQL query execution, triggering full path disclosure. Possibly resultant from more general SQL injection issue. |
| CVE-2005-0459 | chain: product does not protect against direct request of a library file, leading to resultant path disclosure when the file does not successfully execute. |
| CVE-2005-0443 | invalid parameter triggers a failure to find an include file, leading to infoleak in error message. |
| CVE-2005-0433 | Various invalid requests lead to information leak in verbose error messages describing the failure to instantiate a class, open a configuration file, or execute an undefined function. |
| CVE-2004-1101 | Improper handling of filename request with trailing "/" causes multiple consequences, including information leak in Visual Basic error message. |
Related Weaknesses
Taxonomy Mappings
- PLOVER: — Product-External Error Message Infoleak
Frequently Asked Questions
What is CWE-211?
CWE-211 (Externally-Generated Error Message Containing Sensitive Information) is a software weakness identified by MITRE's Common Weakness Enumeration. It is classified as a Base-level weakness. 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 langu...
How can CWE-211 be exploited?
Attackers can exploit CWE-211 (Externally-Generated Error Message Containing Sensitive Information) to read application data. This weakness is typically introduced during the Architecture and Design, Implementation, Operation phase of software development.
How do I prevent CWE-211?
Key mitigations include: Configure the application's environment in a way that prevents errors from being generated. For example, in PHP, disable display_errors.
What is the severity of CWE-211?
CWE-211 is classified as a Base-level weakness (Medium abstraction). It has been observed in 6 real-world CVEs.