Session Hijacking in Foreman MCP Server

Executive Summary

This vulnerability exists in the foreman-mcp-server and involves session management. Specifically, the MCP Server improperly caches authenticated client connections and trusts a non-secret session ID without re-validating authentication tokens. Additionally, it logs all newly created session IDs to standard logs. This flaw allows unauthenticated attackers to hijack active administrative sessions.

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Compliance Impact

The vulnerability in foreman-mcp-server allows unauthenticated attackers to hijack active administrative sessions, leading to privilege escalation and potential infrastructure-wide code execution.

Such unauthorized access and privilege escalation could result in unauthorized disclosure, modification, or destruction of sensitive data, which may impact compliance with standards like GDPR and HIPAA that require strict access controls and protection of sensitive information.

However, specific impacts on compliance are not detailed in the provided information.

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Detection Guidance

This vulnerability can be detected by monitoring server logs for the presence of session IDs being logged at the INFO level, as these session IDs are improperly cached and logged by the foreman-mcp-server. Anomalies such as repeated use of the same session ID from different sources or unexpected administrative actions without proper authentication may indicate exploitation.

Specific commands to detect this vulnerability are not provided in the available resources. However, inspecting the foreman-mcp-server logs for entries containing 'mcp-session-id' or similar session identifiers and checking for unauthorized or unusual JSON-RPC requests could help identify exploitation attempts.

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Mitigation Strategies

Immediate mitigation involves updating the foreman-mcp-server to a version where the AuthMiddleware properly validates the foreman_token on every request. This ensures that any mismatched tokens result in a 401 Unauthorized response and session invalidation, preventing session hijacking.

Until an update is applied, administrators should consider restarting the server frequently to invalidate cached sessions, restrict access to server logs to prevent attackers from harvesting session IDs, and monitor for suspicious activity indicating session hijacking.

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Impact Analysis

The vulnerability can lead to privilege escalation and infrastructure-wide code execution. This means an attacker could gain administrative access without authentication and potentially execute malicious code across the entire infrastructure managed by the foreman-mcp-server.

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