attach_user_policy
AI agents use attach_user_policy to create or update resources in Amazon SageMaker AI MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Amazon SageMaker AI MCP Server environment.
This tool modifies IAM permissions by attaching a policy to a user account. This is reversible (policies can be detached) so it is Write rather than Destructive. However, it carries high severity because misuse could grant unintended permissions to users, potentially enabling privilege escalation or unauthorized access to AWS resources.
From the tool's definition Tool name 'attach_user_policy' indicates attaching an IAM policy to a user. The sibling tools include 'add_inline_policy' and 'add_user_to_group' which are clearly policy/permission management operations.
Attacks that exploit this kind of access
attach_user_policy. It is categorised as a Write tool in the Amazon SageMaker AI MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Amazon SageMaker AI MCP Server MCP server in PolicyLayer and add a rule for attach_user_policy: 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 Amazon SageMaker AI MCP Server. Nothing to install.
attach_user_policy is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the attach_user_policy 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 attach_user_policy. 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.
attach_user_policy is provided by the Amazon SageMaker AI MCP Server MCP server (awslabs.sagemaker-ai-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.