CVE-2022-32563 in Sync Gateway
Summary
by MITRE • 06/10/2022
An issue was discovered in Couchbase Sync Gateway 3.x before 3.0.2. Admin credentials are not verified when using X.509 client-certificate authentication from Sync Gateway to Couchbase Server. When Sync Gateway is configured to authenticate with Couchbase Server using X.509 client certificates, the admin credentials provided to the Admin REST API are ignored, resulting in privilege escalation for unauthenticated users. The Public REST API is not impacted by this issue. A workaround is to replace X.509 certificate based authentication with Username and Password authentication inside the bootstrap configuration.
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Analysis
by VulDB Data Team • 06/15/2022
The vulnerability described in CVE-2022-32563 represents a critical authentication bypass flaw within Couchbase Sync Gateway version 3.x prior to 3.0.2. This issue fundamentally undermines the security model of the system by allowing unauthenticated attackers to escalate privileges through a misconfiguration in the authentication mechanism between Sync Gateway and Couchbase Server. The flaw specifically affects the Admin REST API functionality where administrative credentials are completely disregarded when X.509 client-certificate authentication is employed, creating a pathway for unauthorized access to privileged operations.
The technical implementation of this vulnerability stems from improper credential validation within the authentication flow. When Sync Gateway is configured to use X.509 client certificates for authentication with Couchbase Server, the system fails to validate the administrative credentials provided through the Admin REST API. This represents a classic case of insufficient authentication checks, categorized under CWE-287 which addresses improper authentication scenarios. The flaw manifests because the system assumes that certificate-based authentication alone is sufficient for administrative access, completely ignoring the need for proper credential verification that should occur regardless of the authentication method being used.
From an operational impact perspective, this vulnerability creates a severe privilege escalation vector that allows attackers to gain administrative access to the Sync Gateway system without requiring valid administrative credentials. The implications extend beyond simple unauthorized access as the attacker can perform operations such as modifying database configurations, managing users, accessing sensitive data, and potentially compromising the entire underlying data store. The fact that the Public REST API remains unaffected provides some limited protection, but the administrative interface remains fully exposed to exploitation. This vulnerability aligns with ATT&CK technique T1078 which covers legitimate credentials usage, as it allows attackers to leverage administrative capabilities through bypassed authentication controls.
The recommended mitigation strategy involves implementing a more secure authentication approach by switching from X.509 certificate-based authentication to traditional username and password authentication within the bootstrap configuration. This workaround effectively eliminates the vulnerability by removing the problematic authentication path that allows credential bypass. Organizations should also consider implementing additional security controls such as network segmentation, monitoring for unauthorized administrative API access attempts, and regular security assessments of their Couchbase configurations. The vulnerability highlights the importance of proper authentication design principles where multiple authentication factors should be validated independently rather than assuming that one method of authentication automatically grants all necessary privileges.