CVE-2018-3831 in Elasticsearch Alerting
Summary
by MITRE
Elasticsearch Alerting and Monitoring in versions before 6.4.1 or 5.6.12 have an information disclosure issue when secrets are configured via the API. The Elasticsearch _cluster/settings API, when queried, could leak sensitive configuration information such as passwords, tokens, or usernames. This could allow an authenticated Elasticsearch user to improperly view these details.
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Analysis
by VulDB Data Team • 03/25/2020
The vulnerability identified as CVE-2018-3831 represents a critical information disclosure flaw within Elasticsearch's alerting and monitoring capabilities. This issue affects Elasticsearch versions prior to 6.4.1 and 5.6.12, where the _cluster/settings API endpoint fails to properly sanitize sensitive configuration data during query responses. The vulnerability stems from insufficient input validation and output filtering mechanisms that allow authenticated users to access confidential information through legitimate API calls. Security researchers have classified this as an information disclosure weakness that directly violates fundamental security principles of data protection and access control.
The technical implementation flaw occurs within the cluster settings API handler where configuration parameters containing secrets are not adequately redacted or filtered before being returned in API responses. When an authenticated user queries the _cluster/settings endpoint, the system inadvertently includes sensitive fields such as passwords, API tokens, and username credentials in the response payload. This represents a direct violation of the principle of least privilege and demonstrates poor secure coding practices in handling sensitive data within distributed systems. The vulnerability exists because the API response processing logic does not properly distinguish between public configuration settings and confidential credential information, leading to accidental exposure of authentication material.
From an operational impact perspective, this vulnerability creates significant security risks for organizations relying on Elasticsearch for their monitoring and alerting infrastructure. An authenticated attacker with access to the Elasticsearch cluster can exploit this flaw to gain unauthorized access to sensitive credentials used for various system components, external services, and integration points. The exposure of passwords and tokens could enable lateral movement within the network, access to external systems, and potential escalation of privileges. This information disclosure vulnerability directly maps to attack patterns described in the MITRE ATT&CK framework under the Information Discovery tactic, where adversaries seek to gather sensitive data from compromised systems.
Organizations should immediately implement mitigations including upgrading to Elasticsearch versions 6.4.1 or 5.6.12 where this vulnerability has been patched. Additionally, administrators should review and restrict API access permissions to minimize the attack surface for authenticated users. The fix implemented by Elasticsearch developers involves enhanced sanitization of API responses to prevent sensitive configuration parameters from being returned in cluster settings queries. This remediation aligns with CWE-200 standards for information exposure and follows best practices recommended by NIST for securing distributed database systems. Security teams should also implement monitoring for unusual API query patterns and conduct regular audits of configuration settings to detect potential exploitation attempts.