Lists IAM users in the AWS account.
AI agents call list_iam_users to retrieve information from AWS MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about IAM users without creating, modifying, deleting, or executing any operations. It is a straightforward data query operation. Severity is low because listing IAM users is informational and does not expose sensitive credentials or enable direct account compromise, though it does reveal organizational structure.
From the tool's definition Tool name 'list_iam_users' and description 'Lists IAM users in the AWS account' indicate a query/retrieval operation with no modification or side effects. The server is explicitly described as 'read-only'.
Attacks that exploit this kind of access
Lists IAM users in the AWS account. It is categorised as a Read tool in the AWS MCP Server MCP Server, which means it retrieves data without modifying state.
Register the AWS MCP Server MCP server in PolicyLayer and add a rule for list_iam_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 AWS MCP Server. Nothing to install.
list_iam_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_iam_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_iam_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_iam_users is provided by the AWS MCP Server MCP server (sergiosediq/aws-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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