AI agents call list_users to retrieve information from OpenCTI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves a list of users from the OpenCTI system. It performs no modifications, deletions, or side effects—it only returns data. The operation is read-only and informational in nature. Severity is low because exposing a user list, while potentially sensitive, does not enable direct harm; an AI agent listing users cannot compromise security or cause damage through this tool alone.
From the tool's definition Tool name 'list_users' and description '列出所有使用者' (list all users) indicates retrieval of user data without modification or deletion. This is consistent with sibling tools like 'get_user_by_id', 'list_files', 'list_labels' which are all read operations.
Documented attack patterns abuse exactly the kind of access list_users gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OpenCTI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_users:
{
"version": "1",
"default": "deny",
"tools": {
"list_users": {}
}
}list_users is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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列出所有使用者. It is categorised as a Read tool in the OpenCTI MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OpenCTI MCP Server MCP server in PolicyLayer and add a rule for list_users: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches OpenCTI MCP Server. Nothing to install.
list_users is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_users rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for list_users. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
list_users is provided by the OpenCTI MCP Server MCP server (zxzinn/opencti-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 16 OpenCTI MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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16 OpenCTI MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.