Full Report
NamespaceHound is an open-source tool for detecting the risk of potential namespace crossing violations and anonymous access opportunities in multi-tenant clusters.
Analysis Summary
# Tool/Technique: NamespaceHound
## Overview
NamespaceHound is a security analysis tool designed to detect the risk of potential cross-tenant violations in Kubernetes multi-tenant clusters. It helps cluster operators assess security boundaries by analyzing all possible ways to cross isolation mechanisms (like namespaces) and identifies abnormal permissions or configuration exposures, such as anonymous access opportunities. It is also useful for red-teamers to find lateral movement paths within a cluster after initial compromise.
## Technical Details
- Type: Tool
- Platform: Kubernetes Clusters
- Capabilities: Analyzes cluster configuration to map paths for namespace/tenant crossing violations, inspects for anonymous access opportunities, and reports on different types of security boundary breaches.
- First Seen: Not explicitly mentioned, but discussed in the context of the 2023 Kubernetes Security Report.
## MITRE ATT&CK Mapping
This tool primarily aids in the discovery phase of attacks targeting cloud environments, mapping closely to:
- **TA0008 - Lateral Movement**
- T1558.005 - Steal or Forge Kerberos Tickets (Analogy: Stealing credentials/tokens across namespaces)
- T1548.002 - Bypass User Account Control (Analogy: Bypassing namespace isolation controls)
- **TA0005 - Privilege Escalation**
- T1078.004 - Cloud Accounts (Focus on Service Accounts/Cluster Roles)
## Functionality
### Core Capabilities
- **Cross-Tenant Violation Detection:** Analyzes all possible paths for one tenant to interfere with another's resources across namespace boundaries.
- **Anonymous Access Inspection:** Specifically checks cluster configurations for opportunities where anonymous principals can gain access.
- **Targeted Analysis:** Can be run against the entire cluster or focused on a specific namespace (`-n namespace` parameter) to map its potential interference pathways.
### Advanced Features
- **Red Team Utility:** Allows security researchers and red-teamers to map out lateral movement and privilege escalation opportunities following initial cluster access.
- **RBAC Analysis:** Specifically detects high-severity crossings related to Role-Based Access Control (RBAC), such as Service Accounts gaining access to secrets or the ability to create workloads in other namespaces.
- **Non-Persistency:** Does not save cluster data, graphs, or object material locally; it establishes a new connection and performs API server queries on every run.
## Indicators of Compromise
*Note: NamespaceHound is a detection/assessment tool, not an indicator generator.*
- File Hashes: N/A (Source code available on GitHub)
- File Names: N/A
- Registry Keys: N/A
- Network Indicators: N/A (Operates via Kubernetes API queries)
- Behavioral Indicators: Successful execution results in reports detailing potential unauthorized access paths, such as:
- `RBAC_SECRETS_STEALING`: Service account in one namespace accessing secrets in another.
- `RBAC_WORKLOAD_CREATION`: Service account in one namespace creating resources in another.
## Associated Threat Actors
- Cluster Operators (Defensive use)
- Red-teamers and Security Researchers (Offensive mapping)
## Detection Methods
- Signature-based detection: N/A
- Behavioral detection: Monitoring for repeated, extensive read-only API calls across the cluster, characteristic of security auditing tools (though this might generate noise).
- YARA rules: N/A
## Mitigation Strategies
Mitigation strategies focus on hardening Kubernetes multi-tenancy boundaries, which NamespaceHound helps test:
- **Encrypt Hardening:** Avoid using globally scoped resources (like Webhooks) unless dedicated RBAC ClusterRoles are used for tenant separation. Configure `StorageClass` isolation per tenant, using a "Delete" reclaim policy for `PersistentVolumes` if storage is shared.
- **Authentication Hardening:** Disable service account token automounting where not necessary (`automountServiceAccountToken: false` at the pod or kubelet level).
- **Connectivity Hardening:** Implement strict Kubernetes Network Policies to block cross-tenant pod communication and tenant egress connectivity. Using namespace labels for policies is recommended over pod labels.
## Related Tools/Techniques
- **PEACH Framework:** Wiz's security boundary modeling framework that informs the concepts utilized by NamespaceHound for assessing SaaS/PaaS isolation.
- **Kubernetes RBAC/Namespaces:** The foundational security primitives that NamespaceHound analyzes for misconfigurations.