AI agents call list_yara_rules to retrieve information from YaraFlux MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Listing YARA rules is a non-destructive query operation that retrieves and displays existing rules without modification, deletion, or side effects. No execution, creation, or destructive actions occur. The tool falls squarely into the Read category with low severity since it only surfaces information about available threat detection rules.
From the tool's definition Tool name 'list_yara_rules' indicates a retrieval operation. Context shows this MCP server manages YARA rules for threat analysis, and 'list_' is a standard read-only operation pattern.
Documented attack patterns abuse exactly the kind of access list_yara_rules gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and YaraFlux MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_yara_rules:
{
"version": "1",
"default": "deny",
"tools": {
"list_yara_rules": {}
}
}list_yara_rules is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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list_yara_rules. It is categorised as a Read tool in the YaraFlux MCP Server MCP Server, which means it retrieves data without modifying state.
Register the YaraFlux MCP Server MCP server in PolicyLayer and add a rule for list_yara_rules: 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 YaraFlux MCP Server. Nothing to install.
list_yara_rules 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_yara_rules 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_yara_rules. 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_yara_rules is provided by the YaraFlux MCP Server MCP server (threatflux/yaraflux). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from YaraFlux MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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20 YaraFlux MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.