CVE-2023-46672 in Logstash
Summary
by MITRE • 11/15/2023
An issue was identified by Elastic whereby sensitive information is recorded in Logstash logs under specific circumstances.
The prerequisites for the manifestation of this issue are:
* Logstash is configured to log in JSON format https://www.elastic.co/guide/en/logstash/current/running-logstash-command-line.html , which is not the default logging format.
* Sensitive data is stored in the Logstash keystore and referenced as a variable in Logstash configuration.
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Analysis
by VulDB Data Team • 02/14/2025
This vulnerability represents a critical information disclosure weakness in the Elastic Logstash logging platform that arises from improper handling of sensitive data within log output. The issue manifests when Logstash is explicitly configured to output logs in JSON format rather than the default text format, creating a scenario where sensitive information stored in the Logstash keystore becomes inadvertently exposed through log files. The vulnerability stems from the fact that when variables referencing keystore values are processed within the configuration, the system fails to properly sanitize or mask these values before writing them to JSON formatted logs, thereby creating a direct pathway for confidential data leakage.
The technical flaw operates at the intersection of configuration management and logging output processing within the Logstash pipeline. When Logstash processes configuration files that reference keystore variables, the system performs variable substitution but does not adequately filter or redact sensitive values before logging them in JSON format. This behavior creates a situation where authentication credentials, API keys, or other confidential information can be written to log files in plaintext format, making them accessible to unauthorized users who have access to the log storage system. The vulnerability is particularly concerning because it leverages the legitimate use of keystore functionality for managing sensitive data while simultaneously creating an unintended information disclosure channel. This flaw aligns with CWE-200, which addresses improper handling of sensitive information, and demonstrates how security controls can be bypassed through seemingly legitimate configuration practices.
The operational impact of this vulnerability extends beyond simple data exposure to encompass broader security implications for organizations relying on Logstash for log management. Attackers with access to log files or systems where these logs are stored can extract sensitive credentials and authentication tokens, potentially leading to unauthorized system access, privilege escalation, and lateral movement within the network. The vulnerability is particularly dangerous in environments where log files are shared across multiple teams or stored in centralized logging systems that may not have appropriate access controls. Additionally, the issue can compromise compliance with security standards such as pci dss, hipaa, and soc 2, as sensitive data exposure violates fundamental principles of data protection and confidentiality. Organizations may also face increased risk of insider threats, as the vulnerability creates opportunities for malicious actors within the organization to access sensitive information through log files.
Mitigation strategies for this vulnerability must address both immediate configuration changes and long-term security practices within the Logstash environment. The primary recommendation involves configuring Logstash to avoid JSON logging format when sensitive data is present in the configuration, or implementing comprehensive log filtering mechanisms that redact sensitive information before any logging occurs. Organizations should also implement strict access controls on log storage systems, ensuring that only authorized personnel have access to log files containing sensitive information. The implementation of log sanitization processes that automatically identify and mask sensitive data patterns within log output represents a more robust solution. Security teams should also consider implementing monitoring solutions that can detect and alert on the presence of sensitive data patterns in log files, enabling rapid response to potential exposures. Additionally, regular security assessments of Logstash configurations should include checks for keystore variable usage and logging format settings to prevent similar vulnerabilities from emerging in the future. This vulnerability highlights the importance of proper information flow management within security tools and aligns with ATT&CK technique T1567 which addresses credentials from password storage modules, emphasizing the need for comprehensive protection of sensitive data throughout all system components including logging infrastructure.