CVE-2024-21632: Critical Vulnerability in omniauth-microsoft_graph Prior to Version 2.0.0

Overview

CVE-2024-21632 is a vulnerability that affects omniauth-microsoft_graph, a widely used Omniauth strategy for Microsoft’s Graph API. This vulnerability is of significant concern due to its potential to lead to system compromise or data leakage. The severity of this vulnerability is underscored by its CVSS score of 8.6, indicating a high level of threat. It’s essential for organizations utilizing omniauth-microsoft_graph in their infrastructure to understand this vulnerability and take the necessary steps to mitigate its potential impact.

Vulnerability Summary

CVE ID: CVE-2024-21632
Severity: High (8.6 CVSS score)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: Account takeover, potential system compromise or data leakage

Affected Products

Product | Affected Versions

omniauth-microsoft_graph | Prior to 2.0.0

How the Exploit Works

The vulnerability lies in the omniauth-microsoft_graph’s failure to validate the legitimacy of the `email` attribute of the user, nor does it provide or document an option to do so. This lapse makes it susceptible to nOAuth misconfiguration when the `email` is used as a trusted user identifier. A malicious actor could exploit this flaw by manipulating the `email` attribute to gain unauthorized access to user accounts, which could lead to account takeover, potential system compromise, or data leakage.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited. Assume that an attacker intercepts a request and modifies the `email` attribute:

POST /omniauth/microsoft_graph/callback HTTP/1.1
Host: target.example.com
Content-Type: application/json
{
"provider": "microsoft_graph",
"uid": "legitimate_user_id",
"info": {
"email": "attacker_controlled_email@example.com",
"name": "Legitimate User Name"
}
}

In this example, the attacker-controlled email is used as the `email` attribute in the request. If the server trusts the `email` attribute to identify the user, the attacker can gain unauthorized access to the legitimate user’s account.

Mitigation

Users are strongly advised to upgrade to version 2.0.0 of omniauth-microsoft_graph, which contains a fix for this issue. If upgrading is not immediately possible, implementing a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) may serve as temporary mitigation to detect and block exploit attempts. Lastly, ensure that the `email` attribute used for user identification is validated for legitimacy to prevent nOAuth misconfiguration.