This record as markdown: /tools/0xyg3n-claude-c2/firewall-rule.md
What firewall_rule does on Claude C2
AI agents invoke firewall_rule to trigger actions in Claude C2. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why firewall_rule is rated High
Managing firewall rules can open ports, disable protections, or allow malicious traffic through. In the context of this server — which includes AMSI bypass, UAC bypass, browser credential theft, and Defender exclusion tools — this is almost certainly used to weaken network defenses on remote systems.
From the tool's definition 'Manage firewall rule' on a server designed for 'command and control of remote systems' alongside tools like 'amsi_bypass', 'bypassuac', and 'defender_exclude'
Attacks that exploit this kind of access
The rule that runs firewall_rule safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Claude C2, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For firewall_rule, this is the rule to start with:
firewall_rule stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Claude C2, apply this rule, and every firewall_rule call is checked against it from then on.
Questions about firewall_rule
Manage firewall rule. Auto-selects client. It is categorised as a Execute tool in the Claude C2 MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Claude C2 MCP server in PolicyLayer and add a rule for firewall_rule: 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 Claude C2. Nothing to install.
firewall_rule is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the firewall_rule 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 firewall_rule. 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.
firewall_rule is provided by the Claude C2 MCP server (0xyg3n/claude-c2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on Claude C2, and thousands of servers like it.
Across the catalogue