CWE-272: Least Privilege Violation

What is Least Privilege Violation?

• Overview: CWE-272, Least Privilege Violation, occurs when a software application maintains elevated privileges longer than necessary. This vulnerability arises when an application doesn't drop elevated privileges immediately after completing operations requiring such privileges, potentially exposing the application to unnecessary risks.

• Exploitation Methods:

• Attackers can exploit this vulnerability by executing code with higher privileges than necessary, potentially compromising the system.
• Common attack patterns include privilege escalation attacks where attackers gain unauthorized access to higher privilege levels, leading to unauthorized actions on the system.

• Security Impact:

• Direct consequences of successful exploitation include unauthorized access to sensitive data, system configurations, or administrative functions.
• Potential cascading effects involve attackers using the elevated privileges to pivot and exploit other parts of the system or network.
• Business impact can include data breaches, loss of customer trust, financial loss, and legal ramifications due to non-compliance with data protection regulations.

• Prevention Guidelines:

• Specific code-level fixes involve ensuring that applications drop elevated privileges as soon as the privileged operation is complete.
• Security best practices include implementing the principle of least privilege, regularly auditing code for privilege management, and using role-based access controls.
• Recommended tools and frameworks include security libraries and frameworks that support privilege management, automated code analysis tools to detect privilege misuse, and continuous integration pipelines with security checks.

Corgea can automatically detect and fix Least Privilege Violation 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

import os

def perform_sensitive_operation():
    # Assume this operation requires elevated privileges
    os.setuid(0)  # Switch to root user (UID 0)
    
    # Perform operations that require root privileges
    # ...
    
    # Vulnerability: Elevated privilege is not dropped after sensitive operation
    # This can lead to accidental or malicious execution of code with root privileges
    # If any subsequent code is executed, it will run with root privileges, posing a security risk.

How to fix Least Privilege Violation?

The principle of Least Privilege dictates that a system should operate with the minimal set of privileges necessary to complete its function. In the vulnerable example, the program switches to the root user to perform sensitive operations but fails to drop these elevated privileges afterward. This leaves the system vulnerable to potential misuse or security breaches because any subsequent operations will also execute with root privileges.

To fix this vulnerability, immediately drop the elevated privileges as soon as they are no longer needed. The os.setuid() function should be used again to switch back to a non-privileged user. This minimizes the window of opportunity for any malicious code or accidental misuse to exploit the elevated privileges.

Fixed Code Example

import os

def perform_sensitive_operation():
    # Assume this operation requires elevated privileges
    original_uid = os.getuid()  # Capture the current non-privileged user ID
    os.setuid(0)  # Switch to root user (UID 0)
    
    try:
        # Perform operations that require root privileges
        # ...
        pass
    finally:
        # Drop elevated privilege as soon as possible
        os.setuid(original_uid)  # Revert to the original non-privileged user
        # It is crucial to ensure this step is executed even if an error occurs

In the fixed code example, we use a try...finally block to ensure privileges are dropped back to the original user, even if an exception occurs during the sensitive operations. This approach reliably reduces the risk of privilege escalation vulnerabilities by enforcing the Least Privilege principle. Additionally, the original user ID is captured before privilege escalation, ensuring that the program can revert to the correct user.