CVE-2021-41580 in passport-oauth2
Summary
by MITRE • 09/27/2021
** DISPUTED ** The passport-oauth2 package before 1.6.1 for Node.js mishandles the error condition of failure to obtain an access token. This is exploitable in certain use cases where an OAuth identity provider uses an HTTP 200 status code for authentication-failure error reports, and an application grants authorization upon simply receiving the access token (i.e., does not try to use the token). NOTE: the passport-oauth2 vendor does not consider this a passport-oauth2 vulnerability.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability described in CVE-2021-41580 resides within the passport-oauth2 Node.js package, specifically affecting versions prior to 1.6.1. This issue represents a sophisticated authentication bypass scenario that exploits a fundamental flaw in error handling mechanisms during OAuth token acquisition processes. The vulnerability operates under the premise that certain OAuth identity providers may return HTTP 200 status codes while simultaneously indicating authentication failures through response content rather than proper HTTP status code signaling. This misalignment between HTTP status codes and actual authentication outcomes creates a dangerous condition where applications can mistakenly accept invalid authentication responses as valid.
The technical flaw manifests when the passport-oauth2 package fails to properly validate the authentication response from the OAuth provider. When an OAuth identity provider returns an HTTP 200 status code alongside authentication failure indicators within the response body, the vulnerable package does not adequately parse or verify the actual authentication success or failure state. This error handling deficiency creates an authentication bypass opportunity where malicious actors can exploit the system by crafting responses that appear successful to the passport-oauth2 package but actually represent failed authentication attempts. The vulnerability specifically targets applications that grant authorization simply upon receiving an access token without performing additional validation checks, making these systems particularly susceptible to exploitation.
From an operational impact perspective, this vulnerability can result in unauthorized access to protected resources and services within applications that rely on the affected passport-oauth2 package. The exploitation scenario typically involves an attacker who can manipulate the OAuth flow to receive a token that appears valid to the authentication system but actually represents a failed authentication attempt. This creates a situation where legitimate users may be denied access while unauthorized parties can gain access through the flawed authentication process. The vulnerability can be particularly dangerous in environments where the application grants elevated privileges upon successful token receipt without additional verification steps, potentially leading to privilege escalation and data breaches.
The security implications of this vulnerability align with CWE-284, which addresses improper access control in authentication systems, and can be mapped to ATT&CK technique T1078 for valid accounts usage and T1566 for credential harvesting through social engineering or exploitation of authentication flaws. Organizations using vulnerable versions of the passport-oauth2 package should implement immediate mitigations including upgrading to version 1.6.1 or later, implementing additional token validation mechanisms, and ensuring that applications perform comprehensive verification of authentication responses rather than relying solely on token receipt. The vendor's stance that this is not a passport-oauth2 vulnerability does not diminish the risk to affected systems, as the issue stems from how the package handles specific edge cases in OAuth implementations rather than fundamental design flaws in the core authentication mechanism.
Effective mitigation strategies include implementing comprehensive error handling that validates both HTTP status codes and response content, adding explicit token validation steps beyond simple receipt, and ensuring that applications perform additional authentication checks before granting access privileges. Organizations should also consider implementing monitoring and logging mechanisms to detect anomalous authentication patterns that might indicate exploitation attempts. The vulnerability highlights the importance of robust error handling in authentication systems and demonstrates how seemingly minor implementation details can create significant security risks in identity management workflows.