CVE-2022-31176 in Grafana Image Renderer
Summary
by MITRE • 09/03/2022
Grafana Image Renderer is a Grafana backend plugin that handles rendering of panels & dashboards to PNGs using a headless browser (Chromium/Chrome). An internal security review identified an unauthorized file disclosure vulnerability. It is possible for a malicious user to retrieve unauthorized files under some network conditions or via a fake datasource (if user has admin permissions in Grafana). All Grafana installations should be upgraded to version 3.6.1 as soon as possible. As a workaround it is possible to [disable HTTP remote rendering](https://grafana.com/docs/grafana/latest/setup-grafana/configure-grafana/#plugingrafana-image-renderer).
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Analysis
by VulDB Data Team • 10/13/2022
The vulnerability identified as CVE-2022-31176 affects Grafana Image Renderer, a backend plugin designed to generate PNG images of panels and dashboards using headless browser technology. This plugin serves as a critical component in Grafana's visualization ecosystem, enabling users to export dashboard content for reporting and sharing purposes. The flaw represents an unauthorized file disclosure vulnerability that could potentially allow malicious actors to access sensitive files within the system. The security review that uncovered this issue highlights the importance of continuous security assessment in complex software environments where multiple components interact with each other.
The technical implementation of this vulnerability stems from insufficient input validation and access control mechanisms within the image rendering plugin. When Grafana processes requests to render images, the plugin accepts external inputs that are not properly sanitized before being used to access local file system resources. This weakness becomes particularly dangerous when combined with network conditions that allow for crafted requests or when attackers have administrative privileges within Grafana. The vulnerability can be exploited through a fake datasource mechanism, which allows attackers to manipulate the rendering process and potentially access files that should otherwise be restricted. This flaw aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a classic case of path traversal vulnerability.
The operational impact of this vulnerability extends beyond simple data exposure, as it could potentially lead to complete system compromise when combined with other attack vectors. An attacker with access to a Grafana instance could use this vulnerability to retrieve configuration files, database credentials, or other sensitive artifacts stored on the server. The risk is particularly elevated for organizations that rely heavily on Grafana for monitoring and operational dashboards, as these systems often contain sensitive operational data. The vulnerability's exploitation potential increases significantly when administrative permissions are compromised, as the attacker could then leverage the rendering plugin to access files that are typically protected by file system permissions and access controls. This scenario represents a critical weakness in Grafana's security model and could enable attackers to escalate their privileges or gain deeper system access.
Organizations should immediately upgrade to Grafana version 3.6.1 to remediate this vulnerability, as this represents the most effective solution to address the underlying security flaw. The upgrade process should include comprehensive testing to ensure that existing dashboards and rendering functionality continue to operate correctly. As a temporary mitigation measure, administrators can disable HTTP remote rendering through the Grafana configuration settings, which effectively prevents the exploitation of this vulnerability while maintaining core functionality. This workaround aligns with the principle of least privilege and demonstrates the importance of configuring security settings appropriately. The vulnerability also highlights the need for organizations to implement proper access controls and monitoring for their Grafana installations, as the attack surface increases with the number of users and the complexity of dashboard configurations. Additionally, the incident underscores the necessity of regular security assessments and the importance of maintaining up-to-date software components to prevent exploitation of known vulnerabilities. The ATT&CK framework would classify this vulnerability under T1078 Valid Accounts and T1566 Phishing, as it leverages legitimate administrative access to exploit the rendering plugin functionality, making detection more challenging for security monitoring systems.