Need

Enforce the usage of the X-Content-Type-Options HTTP header

Context

• Usage of Python 3 for writing and executing Python code
• Usage of Django for building web applications in Python

Description

Non compliant code

        from django.http import HttpResponse

def some_view(request):
    response = HttpResponse()
    # Here is the vulnerability, the response does not set the X-Content-Type-Options HTTP header
    return response
        
        

The above code represents a Django view function that returns an HttpResponse object without setting the X-Content-Type-Options HTTP header. This header is used to protect the website from MIME type confusion attacks. It can prevent the browser from interpreting files as a different MIME type to what is specified in the Content-Type HTTP header.

The absence of this header means that the website may be vulnerable to certain types of attacks. For example, an attacker could try to exploit this vulnerability by tricking the browser into interpreting a file as a different type, potentially leading to code execution or other unwanted behaviors.

In the provided code, the HttpResponse object is created and returned without setting the X-Content-Type-Options HTTP header, making it vulnerable.

Steps

• Import the necessary module for setting HTTP headers in Django.
• In the function that generates the HTTP response, after creating the HttpResponse object, set the X-Content-Type-Options HTTP header to 'nosniff'.
• This can be done by accessing the 'X-Content-Type-Options' key of the HttpResponse object's 'headers' attribute and setting its value to 'nosniff'.
• This header tells the browser to not try to interpret the content as something else than declared by the content type.

Compliant code

        from django.http import HttpResponse

def some_view(request):
    response = HttpResponse()
    # Set the X-Content-Type-Options HTTP header
    response["X-Content-Type-Options"] = "nosniff"
    return response
        
        

The original code was vulnerable because it did not set the X-Content-Type-Options HTTP header in the response. This header is used to prevent the browser from interpreting the content as a different type than what is declared by the content type.

The fixed code includes a line that sets the X-Content-Type-Options HTTP header to nosniff for the HttpResponse object. This is done by accessing the X-Content-Type-Options key of the HttpResponse object's headers and setting its value to nosniff.

The nosniff option tells the browser to not try to interpret the content as something else than declared by the content type. This helps to prevent certain types of security vulnerabilities, such as MIME type confusion attacks.

References

• 132. Insecure or unset HTTP headers - X-Content-Type-Options