CVE-2022-3920 in Consul
Summary
by MITRE • 11/16/2022
HashiCorp Consul and Consul Enterprise 1.13.0 up to 1.13.3 do not filter cluster filtering's imported nodes and services for HTTP or RPC endpoints used by the UI. Fixed in 1.14.0.
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Analysis
by VulDB Data Team • 12/19/2022
HashiCorp Consul and Consul Enterprise versions 1.13.0 through 1.13.3 contain a critical security flaw that affects the cluster filtering mechanism within the HTTP and RPC endpoints utilized by the user interface. This vulnerability stems from insufficient validation and filtering of imported nodes and services, allowing unauthorized access to cluster information that should be restricted. The flaw exists in the way the system processes and exposes cluster data through the web interface and remote procedure call mechanisms, creating a potential pathway for attackers to gain visibility into nodes and services that are not intended for their access level. This issue represents a direct violation of the principle of least privilege and could enable attackers to gather sensitive information about the service mesh infrastructure, including node configurations, service registrations, and potentially identifying vulnerable components within the cluster.
The technical implementation of this vulnerability involves the failure of the cluster filtering logic to properly sanitize imported node and service data before exposing it through the UI endpoints. When users interact with the Consul web interface or make RPC calls to retrieve cluster information, the system should apply appropriate access controls and filtering mechanisms to ensure that only authorized data is returned. However, in the affected versions, this filtering process is bypassed or inadequately implemented, resulting in the exposure of potentially sensitive cluster metadata. This flaw specifically impacts the HTTP and RPC communication channels that are integral to the Consul user interface functionality, making it particularly concerning for organizations that rely heavily on the web-based management capabilities of the platform. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and represents a classic case of inadequate input validation and access control enforcement.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers to perform reconnaissance activities that facilitate more sophisticated attacks against the Consul infrastructure. An attacker who gains access to the UI or RPC endpoints could potentially map the entire service mesh topology, identify service dependencies, and discover vulnerable services that might be targeted in subsequent exploitation phases. This information could be leveraged to craft targeted attacks against specific services or to understand the overall architecture of the system for privilege escalation attempts. The vulnerability also creates potential risks for organizations that rely on Consul for service discovery and configuration management, as it could expose internal service endpoints and their configurations to unauthorized parties. From an ATT&CK perspective, this vulnerability maps to techniques involving reconnaissance and credential access, as it enables adversaries to gather intelligence about the target environment and potentially identify weak points in the service mesh infrastructure.
Organizations using affected Consul versions should immediately implement the remediation by upgrading to Consul 1.14.0 or later, which contains the necessary patches to address the cluster filtering bypass. Additionally, administrators should review and tighten access controls for the Consul UI and RPC endpoints, implementing additional authentication layers and network segmentation where possible. The patch addresses the root cause by implementing proper filtering mechanisms that ensure imported nodes and services are appropriately validated before being exposed through the HTTP and RPC endpoints. Security teams should also conduct thorough audits of their Consul configurations to identify any potential misconfigurations that might compound the risks associated with this vulnerability. Organizations should monitor for any signs of unauthorized access attempts or unusual activity in their Consul clusters, particularly around the UI and RPC endpoints, as this vulnerability could be exploited to gain unauthorized visibility into critical infrastructure components.