Security controls bypass or absence - Data creation
Need
Enforcement of proper security controls for data creation
Context
- Usage of TypeScript for statically typed JavaScript development
- Usage of Express for building web applications and APIs
Description
Non compliant code
import express from 'express';
const app = express();
app.post('/policy', (req, res) => {
const { beneficiaries } = req.body;
if (beneficiaries.length > 4) {
// Vulnerability: Bypassing the restriction on the number of beneficiaries
// No validation is performed on the server side
// Multiple beneficiaries can be associated with a request
}
// Process the policy creation logic
// ...
res.status(200).json({ message: 'Policy created successfully' });
});
app.listen(3000, () => {
console.log('Server is running on port 3000');
});
The vulnerability in the given code is related to the absence of server-side validation for the number of beneficiaries allowed when creating a policy.
In the code, when a POST request is made to the '/policy' endpoint, the code extracts the 'beneficiaries' data from the request body. It then checks if the length of the 'beneficiaries' array is greater than 4. If it is, the code does not perform any validation or restriction, allowing multiple beneficiaries to be associated with the policy request.
This vulnerability allows an attacker to bypass the intended restriction and associate an unlimited number of beneficiaries with a policy request. This can lead to an integrity issue as it violates the intended business logic and potentially allows unauthorized access or manipulation of data.
To mitigate this vulnerability, it is recommended to implement server-side validation to enforce the restriction on the number of beneficiaries allowed. This can be done by checking the length of the 'beneficiaries' array and returning an appropriate error response if the limit is exceeded.
Steps
- Validate the number of beneficiaries on the server side before processing the policy creation logic.
- Add server-side validation to ensure that the number of beneficiaries does not exceed the desired limit (e.g., 4).
- If the number of beneficiaries exceeds the limit, return an appropriate error response to the client.
- Implement input validation for all other fields in the application to prevent other security control bypass vulnerabilities.
Compliant code
import express from 'express';
const app = express();
app.use(express.json());
app.post('/policy', (req, res) => {
const { beneficiaries } = req.body;
if (beneficiaries.length > 4) {
return res.status(400).json({ error: 'Exceeded the maximum number of beneficiaries' });
}
// Process the policy creation logic
// ...
return res.status(200).json({ message: 'Policy created successfully' });
});
app.listen(3000, () => {
console.log('Server is running on port 3000');
});
The fixed code addresses the vulnerability by implementing server-side validation to ensure that the maximum number of beneficiaries allowed is not exceeded.
The code uses the Express framework to create an API endpoint for creating a policy. It starts by importing the necessary dependencies and initializing the Express application.
The app.use(express.json()) middleware is used to parse incoming requests with JSON payloads.
The app.post('/policy', ...) route handles the POST request to create a policy. It extracts the beneficiaries data from the request body.
The fixed code then checks if the number of beneficiaries exceeds the maximum allowed (4 in this case). If it does, it returns a 400 Bad Request response with an error message indicating that the maximum number of beneficiaries has been exceeded.
If the number of beneficiaries is within the allowed limit, the code proceeds to process the policy creation logic. This part is not shown in the code snippet but can be implemented as per the application's requirements.
Finally, the code returns a 200 OK response with a success message indicating that the policy has been created successfully.
By validating the number of beneficiaries on the server-side, the code ensures that only a limited number of beneficiaries can be associated with a policy, preventing the integrity of the data from being compromised.