CVE-2024-11994 is a medium-severity vulnerability affecting Elastic APM Server version 8.0.0. The issue stems from the server's handling of partially failed bulk index requests, where parts of the document body may be inadvertently logged in error logs. This behavior can lead to the exposure of sensitive information contained within those documents to unauthorized actors who have access to the APM Server logs. Specifically, the vulnerability is categorized under CWE-200, indicating an exposure of sensitive information to unauthorized parties. The vulnerability requires an attacker to have network-level access (Attack Vector: Adjacent) and low privileges (PR:L), but does not require user interaction. The CVSS 3.1 vector (AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) indicates that the confidentiality impact is high, while integrity and availability impacts are none. This means that while the vulnerability does not allow modification or disruption of service, it can lead to significant leakage of confidential data. The vulnerability is present in Elastic APM Server 8.0.0, a component widely used for application performance monitoring and logging in distributed systems. No known exploits are currently reported in the wild, and no patches or mitigations have been officially released at the time of publication. The root cause is the logging mechanism that does not adequately sanitize or exclude sensitive document content when bulk indexing partially fails, resulting in sensitive data being recorded in error logs accessible to users with log access privileges. This can be particularly problematic in environments where logs are accessible by multiple teams or stored in less secure locations, increasing the risk of unauthorized data disclosure.

For European organizations, the exposure of sensitive information through Elastic APM Server logs can have significant repercussions. Many organizations in sectors such as finance, healthcare, telecommunications, and government rely on Elastic APM for monitoring critical applications. The inadvertent logging of sensitive data could lead to breaches of GDPR and other data protection regulations, resulting in legal penalties and reputational damage. Confidential information such as personally identifiable information (PII), financial data, or proprietary business information could be exposed if contained in the document bodies indexed by APM Server. Since the vulnerability requires low privileges but network adjacency, insider threats or compromised internal systems could exploit this to access sensitive logs. The impact is heightened in multi-tenant or cloud environments where log access controls may be less stringent. Additionally, organizations with centralized logging and monitoring infrastructures that aggregate Elastic APM logs could inadvertently expose sensitive data to a broader audience. The lack of integrity and availability impact means system operations remain unaffected, but the confidentiality breach alone is critical in regulated industries. European organizations must consider the compliance risks and potential for data leakage when deploying Elastic APM Server 8.0.0 without mitigations.

1. Restrict access to Elastic APM Server logs strictly on a need-to-know basis, ensuring only authorized personnel can view error logs. 2. Implement log management solutions that support redaction or masking of sensitive data before storage or access. 3. Monitor bulk indexing operations for failures and review logs for inadvertent sensitive data exposure. 4. Where possible, avoid sending highly sensitive information in documents indexed by APM Server or sanitize data before indexing. 5. Deploy network segmentation to limit access to APM Server interfaces and logs, reducing the attack surface to adjacent network actors. 6. Use role-based access control (RBAC) and audit logging to track access to logs and detect unauthorized access attempts. 7. Stay updated with Elastic’s security advisories for patches or configuration changes addressing this vulnerability. 8. Consider deploying additional application-layer encryption or tokenization for sensitive fields before ingestion into Elastic APM. 9. Conduct internal security reviews and penetration tests focusing on log exposure and data leakage risks related to APM Server deployments.