AI agents call zeek_expired_certs to retrieve information from Zeek without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and analyzes certificate data from Zeek logs to detect security indicators. It performs read-only analysis without side effects—no data is modified, deleted, executed, or moved. The tool is part of a security monitoring context where it helps analysts investigate existing network events rather than alter infrastructure or trigger actions.
From the tool's definition Tool name 'zeek_expired_certs' and description 'Find connections using expired or self-signed certificates' indicate a query/search operation over existing Zeek network security logs to identify suspicious certificate patterns.
Attacks that exploit this kind of access
Find connections using expired or self-signed certificates - potential indicators of man-in-the-middle or malicious infrastructure. It is categorised as a Read tool in the Zeek MCP Server, which means it retrieves data without modifying state.
Register the Zeek MCP server in PolicyLayer and add a rule for zeek_expired_certs: 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 Zeek. Nothing to install.
zeek_expired_certs 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 zeek_expired_certs 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 zeek_expired_certs. 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.
zeek_expired_certs is provided by the Zeek MCP server (solomonneas/zeek-mcp). 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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