syscall_resolve_ssn
Resolve NT syscall service numbers (SSN) from on-disk ntdll.dll. Parses the export table to extract Zw* → SSN mappings and locates a syscall;ret gadget for direct invocation stubs. Win32 only.
This record as markdown: /tools/io-github-vmoranv-jshookmcp/syscall-resolve-ssn.md
What syscall_resolve_ssn does on Jshookmcp
AI agents invoke syscall_resolve_ssn to trigger actions in Jshookmcp. 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 syscall_resolve_ssn is rated High
Extracts syscall numbers and gadgets enabling direct kernel invocation, bypassing security controls.
From the tool's definition Resolve NT syscall service numbers, locates syscall;ret gadget for direct invocation
Attacks that exploit this kind of access
The rule that runs syscall_resolve_ssn safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For syscall_resolve_ssn, this is the rule to start with:
syscall_resolve_ssn 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 Jshookmcp, apply this rule, and every syscall_resolve_ssn call is checked against it from then on.
Questions about syscall_resolve_ssn
Resolve NT syscall service numbers (SSN) from on-disk ntdll.dll. Parses the export table to extract Zw* → SSN mappings and locates a syscall;ret gadget for direct invocation stubs. Win32 only. It is categorised as a Execute tool in the Jshookmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Jshook MCP server in PolicyLayer and add a rule for syscall_resolve_ssn: 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 Jshookmcp. Nothing to install.
syscall_resolve_ssn 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 syscall_resolve_ssn 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 syscall_resolve_ssn. 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.
syscall_resolve_ssn is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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