Information Exposure Through Error Message

ID

python.information_exposure_through_error_message

Severity

low

Resource

Information Leak

Language

Python

Tags

CWE:209, NIST.SP.800-53, OWASP:2021:A4, PCI-DSS:6.5.5

Description

Generation of error messages containing sensitive information.

Rationale

Error messages are an integral part of application development, used to communicate issues in the code to the developers. However, in a production environment, overly detailed error messages can become a security liability. For example, stack traces or database exception messages can disclose information about file paths, internal IP addresses, stack traces, database structure, or library versions, all of which can be exploited if in the hands of a malicious user.

In Python applications, improper handling of errors can lead to such exposures:

def divide_numbers(x, y):
    try:
        return x / y
    except Exception as e:
        return str(e)

result = divide_numbers(5, 0)
print(result)

In the example above, dividing by zero will cause an exception, revealing the error message to the user directly. If the application were live, this would expose internal logic to potential attackers.

Remediation

To remediate instances of information exposure through error messages, the primary action is to limit the detail provided in exceptions sent to the end-user. Consider the following steps:

  1. Generic Error Messages: Ensure that user-facing error messages do not reveal detailed system information. Use generic language and avoid technical specifics.

  2. Centralized Error Handling: Employ a global exception handling strategy using a framework that standardizes error responses across your applications.

  3. Logging: Utilize logging frameworks to log detailed error information securely, ensuring logs do not expose sensitive data.

  4. Security Review: Review all instances where exceptions are caught and handled, ensuring they follow the guidelines above, particularly in areas of code that are publicly accessible.

Following these steps reduces the risk of sensitive data exposure through error messages, thereby strengthening the security posture of the application.

References