CVE-2023-22893: Strapi AWS Cognito Auth Bypass Vulnerability

CVE-2023-22893 Overview

CVE-2023-22893 is an authentication bypass vulnerability in Strapi, a popular open-source headless CMS, affecting versions through 4.5.5. The vulnerability exists in the OAuth flow when the AWS Cognito login provider is used for authentication. Strapi fails to properly verify access or ID tokens issued during the OAuth process, allowing remote attackers to forge JWT tokens using the 'None' type algorithm and bypass authentication entirely.

Critical Impact

Remote attackers can forge ID tokens to impersonate any user authenticated through AWS Cognito, potentially gaining unauthorized access to administrative functions, sensitive content, and backend systems without valid credentials.

Affected Products

• Strapi versions up to and including 4.5.5
• Strapi deployments using AWS Cognito as the OAuth authentication provider
• Applications relying on Strapi's built-in OAuth token validation

Discovery Timeline

• 2023-04-19 - CVE-2023-22893 published to NVD
• 2025-11-07 - Last updated in NVD database

Technical Details for CVE-2023-22893

Vulnerability Analysis

This vulnerability represents a classic JWT algorithm confusion attack (CWE-287: Improper Authentication). The core issue stems from Strapi's failure to enforce strict algorithm validation when processing JWT tokens during the AWS Cognito OAuth authentication flow.

When a user authenticates via AWS Cognito, Strapi receives an ID token that should be cryptographically signed to verify its authenticity. However, the vulnerable versions of Strapi do not properly validate the signing algorithm specified in the JWT header. This oversight allows attackers to craft malicious tokens that specify the alg: none algorithm, effectively creating unsigned tokens that Strapi incorrectly accepts as valid.

The attack requires no prior authentication and can be executed remotely over the network. An attacker only needs to understand the expected JWT structure and the user identifiers used within the target Strapi deployment. Once a forged token is accepted, the attacker assumes the identity of the impersonated user with all associated privileges.

Root Cause

The root cause is insufficient validation of the JWT algorithm field in Strapi's OAuth token verification logic. When processing tokens from AWS Cognito, the application fails to:

1. Explicitly reject tokens using the none algorithm
2. Enforce a whitelist of acceptable signing algorithms
3. Verify that the token's claimed algorithm matches the expected cryptographic verification method

This allows attackers to bypass the cryptographic signature verification by simply declaring that no signature is required, a technique known as the "algorithm none" attack that has affected numerous JWT implementations.

Attack Vector

The attack can be executed remotely over the network without any user interaction or prior authentication. An attacker crafts a malicious JWT token with the following characteristics:

1. The JWT header specifies "alg": "none" to indicate no signature verification is needed
2. The payload contains the victim's user identifier (such as email or user ID) obtained through reconnaissance
3. The signature portion is left empty or omitted entirely

When this forged token is submitted to a vulnerable Strapi instance during an authentication request, the application incorrectly accepts it as valid, granting the attacker access as the impersonated user. The attacker can target any user account, including administrators, potentially leading to complete compromise of the Strapi deployment.

The attack does not require complex tooling—standard JWT manipulation utilities or even manual token construction is sufficient. Technical details of this vulnerability class are documented in the GhostCamm security research.

Detection Methods for CVE-2023-22893

Indicators of Compromise

• JWT tokens in authentication requests with "alg": "none" or "alg": "None" in the header
• Authentication requests containing JWT tokens with empty or missing signature sections
• Unusual successful authentication events for AWS Cognito users without corresponding Cognito authentication logs
• Access patterns from unfamiliar IP addresses immediately following suspicious authentication attempts

Detection Strategies

• Implement Web Application Firewall (WAF) rules to inspect and block JWT tokens specifying the none algorithm
• Monitor authentication logs for tokens where the signature component is absent or malformed
• Correlate Strapi authentication events with AWS Cognito CloudTrail logs to identify forged tokens
• Deploy network intrusion detection signatures targeting JWT algorithm manipulation patterns

Monitoring Recommendations

• Enable detailed logging for all OAuth authentication flows in Strapi applications
• Configure alerts for any authentication attempts using non-standard JWT algorithms
• Implement real-time monitoring of successful authentications that lack corresponding IdP-side records
• Review audit logs for privilege escalation or administrative actions following suspicious authentication events

How to Mitigate CVE-2023-22893

Immediate Actions Required

• Upgrade Strapi to version 4.6.0 or later which includes the security fix for this vulnerability
• Audit authentication logs to identify any potential exploitation attempts
• Review user sessions and revoke any suspicious or unauthorized access
• Consider temporarily disabling AWS Cognito authentication if immediate patching is not possible

Patch Information

Strapi has addressed this vulnerability in versions released after 4.5.5. Organizations should upgrade to the latest stable release to receive this and other security fixes. The official Strapi Release Notes provide detailed changelog information, and the Strapi Security Vulnerability Blog contains the vendor's security disclosure.

Workarounds

• If upgrading is not immediately possible, implement a reverse proxy or WAF rule to reject requests containing JWT tokens with alg: none or alg: None
• Consider switching to an alternative OAuth provider until the vulnerability is patched
• Implement additional application-layer validation to verify tokens against AWS Cognito's public keys before accepting authentication
• Restrict network access to the Strapi admin panel and API endpoints to trusted IP ranges

# Example nginx configuration to block JWT none algorithm
# Add to server block protecting Strapi endpoints
location /api/auth/ {
    if ($http_authorization ~* "\"alg\":\s*\"[Nn]one\"") {
        return 403;
    }
    proxy_pass http://strapi_backend;
}