Low Risk

crtsh_search

Search Certificate Transparency logs via crt.sh. Returns unique subdomains and certificate details (issuer, validity, SANs).

Part of the Osint MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

AI agents call crtsh_search to retrieve information from Osint without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.

Even though crtsh_search only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.

Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.

osint.yaml
tools:
  crtsh_search:
    rules:
      - action: allow

See the full Osint policy for all 37 tools.

Tool Name crtsh_search
Category Read
MCP Server Osint MCP Server
Risk Level Low

View all 37 tools →

Agents calling read-class tools like crtsh_search have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

Other tools in the Read risk category across the catalogue. The same policy patterns (rate-limit, allow) apply to each.

What does the crtsh_search tool do? +

Search Certificate Transparency logs via crt.sh. Returns unique subdomains and certificate details (issuer, validity, SANs).. It is categorised as a Read tool in the Osint MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on crtsh_search? +

Add a rule in your Intercept YAML policy under the tools section for crtsh_search. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Osint MCP server.

What risk level is crtsh_search? +

crtsh_search is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit crtsh_search? +

Yes. Add a rate_limit block to the crtsh_search rule in your Intercept 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.

How do I block crtsh_search completely? +

Set action: deny in the Intercept policy for crtsh_search. 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.

What MCP server provides crtsh_search? +

crtsh_search is provided by the Osint MCP server (osint-mcp-server). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Let agents act without letting them run wild.

Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.

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