This record as markdown: /tools/0xyg3n-claude-c2/amsi-bypass.md
What amsi_bypass does on Claude C2
AI agents invoke amsi_bypass 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 amsi_bypass is rated High
Bypassing AMSI is a well-known attacker technique that disables Windows' antimalware scanning capabilities, allowing arbitrary malicious code to run undetected. This is an Execute-category action with critical severity because it directly undermines host security controls and is a prerequisite step for malware deployment, privilege escalation, and further compromise.
From the tool's definition 'Bypass AMSI' — AMSI (Antimalware Scan Interface) is a Windows security feature; bypassing it disables malware scanning, enabling execution of malicious code without detection.
Attacks that exploit this kind of access
The rule that runs amsi_bypass 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 amsi_bypass, this is the rule to start with:
amsi_bypass 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 amsi_bypass call is checked against it from then on.
Questions about amsi_bypass
Bypass AMSI. 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 amsi_bypass: 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.
amsi_bypass 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 amsi_bypass 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 amsi_bypass. 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.
amsi_bypass 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.
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