CWE-1023: Incomplete Comparison with Missing Factors

What is Incomplete Comparison with Missing Factors?

• Overview:

• CWE-1023 occurs when a comparison between entities fails to include all necessary factors, leading to incomplete assessments. This can cause the software to make incorrect decisions such as selecting the wrong object or making faulty security determinations.

• Exploitation Methods:

• Attackers can exploit this vulnerability by manipulating the comparison process to bypass security checks or gain unauthorized access.
• Common attack patterns include supplying data that exploits the missing factors to achieve unintended behavior from the software.

• Security Impact:

• Direct consequences include unauthorized access, incorrect data processing, and faulty control flow.
• Potential cascading effects involve further exploitation opportunities, such as privilege escalation or data leakage.
• Business impact can range from loss of trust, financial loss, and legal repercussions due to compromised data integrity and confidentiality.

• Prevention Guidelines:

• Specific code-level fixes include ensuring all relevant factors are incorporated into comparisons and validations.
• Security best practices involve rigorous testing and code review processes to identify and address incomplete comparisons.
• Recommended tools and frameworks include static analysis tools to detect potential comparison vulnerabilities and implementing coding standards that mandate comprehensive factor inclusion.

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Technical Details

Likelihood of Exploit: Not specified

Affected Languages: Not Language-Specific

Affected Technologies: Not specified

Vulnerable Code Example

Python Example

class User:
    def __init__(self, username, email, role):
        self.username = username
        self.email = email
        self.role = role

def is_same_user(user1, user2):
    # Vulnerable comparison: only compares username
    # This could lead to incorrect equality if two users have the same username but different emails or roles
    return user1.username == user2.username

How to fix Incomplete Comparison with Missing Factors?

Fixed Code Example

class User:
    def __init__(self, username, email, role, user_id):
        self.username = username
        self.email = email
        self.role = role
        self.user_id = user_id

def is_same_user(user1, user2):
    # Fixed comparison: compares user_id for identity
    # Ensures that comparison is based on unique and comprehensive attributes
    return user1.user_id == user2.user_id

In the fixed code, the is_same_user function now uses user_id to determine if two User objects represent the same user. This approach assumes user_id is a unique identifier, which is a best practice in user management systems. This fix ensures that no matter how similar other attributes like username or email are, the comparison relies on a unique and consistent attribute, preventing unauthorized access or privilege escalation.