CVE-2023-52139 in Misskey
Summary
by MITRE • 12/29/2023
Misskey is an open source, decentralized social media platform. Third-party applications may be able to access some endpoints or Websocket APIs that are incorrectly specified as [kind](https://github.com/misskey-dev/misskey/blob/406b4bdbe79b5b0b68fcdcb3c4b6e419460a0258/packages/backend/src/server/api/endpoints.ts#L811) or [secure](https://github.com/misskey-dev/misskey/blob/406b4bdbe79b5b0b68fcdcb3c4b6e419460a0258/packages/backend/src/server/api/endpoints.ts#L805) without the user's permission and perform operations such as reading or adding non-public content. As a result, if the user who authenticated the application is an administrator, confidential information such as object storage secret keys and SMTP server passwords will be leaked, and general users can also create invitation codes without permission and leak non-public user information. This is patched in version [2023.12.1](https://github.com/misskey-dev/misskey/commit/c96bc36fedc804dc840ea791a9355d7df0748e64).
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 01/21/2024
The vulnerability CVE-2023-52139 affects Misskey, an open source decentralized social media platform that allows third-party applications to interact with its API endpoints and websocket APIs. This security flaw stems from improper access control configuration where certain endpoints are incorrectly marked as either "kind" or "secure" in the backend implementation. The misconfiguration enables unauthorized third-party applications to bypass normal permission checks and access protected resources that should only be available to authenticated users with proper authorization levels.
The technical implementation of this vulnerability resides in the API endpoint definition file where access control mechanisms are improperly configured. Specifically, the backend code at line 811 and 805 in the endpoints.ts file contains incorrect specification of access levels for various API endpoints. This misclassification allows applications that have been granted authentication tokens to access resources that should require additional authorization checks or user consent before execution. The flaw operates under CWE-284 Access Control Bypass, where insufficient access control mechanisms permit unauthorized access to protected resources.
The operational impact of this vulnerability extends beyond simple unauthorized data access. When an authenticated user who has granted permissions to a third-party application is an administrator, the vulnerability enables complete exposure of sensitive system information including object storage secret keys and SMTP server passwords. These credentials represent critical system components that could allow attackers to compromise entire infrastructure. General users can also exploit this vulnerability to create invitation codes without proper authorization, leading to unauthorized user account creation and potential data leakage. The vulnerability essentially creates a backdoor for privilege escalation and unauthorized information disclosure.
The attack vector follows the ATT&CK framework pattern of privilege escalation through API abuse, where legitimate authenticated applications are leveraged to access unauthorized resources. This represents a significant risk to both system administrators and regular users, as it allows attackers to exploit the trust relationship between users and applications. The vulnerability demonstrates the critical importance of proper access control implementation and the potential for a single misconfiguration to create widespread security implications across different user roles within the system.
Mitigation strategies should focus on implementing proper access control checks for all API endpoints, ensuring that each endpoint correctly validates user permissions before granting access to protected resources. The fix in version 2023.12.1 addresses this by correcting the endpoint access control specifications and implementing proper authorization checks. Organizations should also implement regular security audits of API endpoint configurations, enforce principle of least privilege for third-party applications, and monitor for unauthorized access attempts to sensitive system resources. Additionally, implementing proper logging and monitoring of API access patterns can help detect and respond to potential exploitation attempts of similar vulnerabilities.