CVE-2021-25949

Overview

Prototype pollution vulnerability in ‘set-getter’ version 0.1.0 allows an attacker to cause a denial of service and may lead to remote code execution.

Details

The NPM module `set-getter` can be abused by Prototype Pollution vulnerability since the function `setGetter()` does not check for the type of object before assigning value to the property. Due to this flaw an attacker could create a non-existent property or be able to manipulate the property which leads to Denial of Service or potentially Remote code execution.

PoC Details

The `setGetter()` function accepts `obj, prop, getter` as arguments. Due to the absence of validation on the values passed into the `prop` argument, an attacker can supply a malicious value by adjusting the value to include the `__proto__` property. Since there is no validation before assigning the property to check whether the assigned argument is the Object's own property or not, the property `polluted` will be directly assigned to the new object thereby polluting the Object prototype. Later in the code, if there is a check to validate `polluted` the value would be substituted as "Yes! It's Polluted" as it had been polluted.

PoC Code

var setGetter = require("set-getter")

var obj = {} console.log("Before : " + {}.polluted);

setGetter(obj,'__proto__.polluted', function (polluted) { return 'Yes! Its Polluted' });

console.log("After : " + {}.polluted);

Affected Environments

0.1.0

Prevention

Upgrade to version 0.1.1