CWE-283: Unverified Ownership

What is Unverified Ownership?

• Overview: The Unverified Ownership vulnerability occurs when a software product fails to check whether a critical resource, like a file or object, is owned or controlled by the appropriate entity, potentially allowing unauthorized access or manipulation.

• Exploitation Methods:

• Attackers may exploit this vulnerability by gaining unauthorized access to resources by masquerading as the legitimate owner.
• Common attack patterns include manipulating identifiers or credentials to access or modify resources they shouldn't have control over.

• Security Impact:

• Direct consequences include unauthorized access, data leakage, or modification of critical resources.
• Potential cascading effects can involve privilege escalation, where attackers gain higher-level access.
• Business impact may include data breaches, loss of customer trust, regulatory fines, and damage to brand reputation.

• Prevention Guidelines:

• Implement strict ownership checks for critical resources, ensuring that operations are performed only by verified and authorized entities.
• Adhere to principles of least privilege and role-based access control to minimize unnecessary access to resources.
• Use recommended tools and frameworks that provide built-in security features for verifying ownership and access controls.

Corgea can automatically detect and fix Unverified Ownership in your codebase. [Try Corgea free today](https://corgea.app).

Technical Details

Likelihood of Exploit: Not specified

Affected Languages: Not Language-Specific

Affected Technologies: Not specified

Vulnerable Code Example

Python Example: Unverified Ownership Vulnerability

class FileManager:
    def delete_user_file(self, user_id, file_id):
        # Vulnerable: Assumes the user owns the file without verification
        # This could allow unauthorized users to delete files they do not own
        delete_file_from_storage(file_id)

In this vulnerable code, the delete_user_file method does not verify if the user_id actually owns the file_id before calling delete_file_from_storage. This oversight could allow an attacker to delete someone else's file by simply knowing the file ID.

How to fix Unverified Ownership?

To fix this vulnerability, we need to ensure that every action performed on a resource is authorized. This involves verifying that the user_id requesting the action indeed owns the file_id. This verification can be done by querying the database or another storage mechanism to confirm the ownership before proceeding with any critical operation like deletion.

Fixed Code Example

class FileManager:
    def __init__(self, database):
        self.database = database

    def delete_user_file(self, user_id, file_id):
        # First, verify ownership of the file by querying the database
        file_owner_id = self.get_file_owner(file_id)
        if file_owner_id != user_id:
            # Raise an error if the user does not own the file
            raise PermissionError("User does not have permission to delete this file")

        # Ownership verified, proceed with deletion
        delete_file_from_storage(file_id)

    def get_file_owner(self, file_id):
        # Simulated database call to get the owner of the file
        # In a real-world scenario, this would involve an actual database query
        return self.database.query_file_owner(file_id)

In the fixed code example, the delete_user_file method first retrieves the owner of the file using get_file_owner(file_id) and compares it with user_id. If the user doesn't own the file, it raises a PermissionError, preventing unauthorized deletion. This ensures that only the legitimate owner can delete their file, effectively mitigating the unverified ownership vulnerability.