hacktricks/pentesting-web/deserialization/basic-java-deserialization-objectinputstream-readobject.md

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In hierdie POST gaan 'n voorbeeld verduidelik word wat `java.io.Serializable` gebruik.

# Serializable

Die Java `Serializable`-koppelvlak (`java.io.Serializable` is 'n merk-koppelvlak wat jou klasse moet implementeer as hulle **geserialiseer** en **gedeserialiseer** moet word. Java objekserialisering (skryf) word gedoen met die [ObjectOutputStream](http://tutorials.jenkov.com/java-io/objectoutputstream.html) en deserialisering (lees) word gedoen met die [ObjectInputStream](http://tutorials.jenkov.com/java-io/objectinputstream.html).

Kom ons kyk na 'n voorbeeld met 'n **klas Persoon** wat **geserialiseer** kan word. Hierdie klas **oorskryf die readObject** funksie, so wanneer **enige objek** van hierdie **klas** **gedeserialiseer** word, gaan hierdie **funksie** **uitgevoer** word.\
In die voorbeeld, die **readObject funksie** van die klas Persoon roep die funksie `eat()` van sy troeteldier aan en die funksie `eat()` van 'n Hond (om een of ander rede) roep 'n **calc.exe** aan. **Ons gaan kyk hoe om 'n Persoon objek te serialiseer en te deserialiseer om hierdie sakrekenaar uit te voer:**

**Die volgende voorbeeld is van [https://medium.com/@knownsec404team/java-deserialization-tool-gadgetinspector-first-glimpse-74e99e493649](https://medium.com/@knownsec404team/java-deserialization-tool-gadgetinspector-first-glimpse-74e99e493649)**
```java
import java.io.Serializable;
import java.io.*;

public class TestDeserialization {
interface Animal {
public void eat();
}
//Class must implements Serializable to be serializable
public static class Cat implements Animal,Serializable {
@Override
public void eat() {
System.out.println("cat eat fish");
}
}
//Class must implements Serializable to be serializable
public static class Dog implements Animal,Serializable {
@Override
public void eat() {
try {
Runtime.getRuntime().exec("calc");
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("dog eat bone");
}
}
//Class must implements Serializable to be serializable
public static class Person implements Serializable {
private Animal pet;
public Person(Animal pet){
this.pet = pet;
}
//readObject implementation, will call the readObject from ObjectInputStream  and then call pet.eat()
private void readObject(java.io.ObjectInputStream stream)
throws IOException, ClassNotFoundException {
pet = (Animal) stream.readObject();
pet.eat();
}
}
public static void GeneratePayload(Object instance, String file)
throws Exception {
//Serialize the constructed payload and write it to the file
File f = new File(file);
ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(f));
out.writeObject(instance);
out.flush();
out.close();
}
public static void payloadTest(String file) throws Exception {
//Read the written payload and deserialize it
ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
Object obj = in.readObject();
System.out.println(obj);
in.close();
}
public static void main(String[] args) throws Exception {
// Example to call Person with a Dog
Animal animal = new Dog();
Person person = new Person(animal);
GeneratePayload(person,"test.ser");
payloadTest("test.ser");
// Example to call Person with a Cat
//Animal animal = new Cat();
//Person person = new Person(animal);
//GeneratePayload(person,"test.ser");
//payloadTest("test.ser");
}
}
```
## Gevolgtrekking

Soos jy in hierdie baie basiese voorbeeld kan sien, verskyn die "kwesbaarheid" hier omdat die **readObject** funksie **ander kwesbare funksies aanroep**.


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<details>

<summary>Ondersteun HackTricks</summary>

* Kyk na die [**subskripsie planne**](https://github.com/sponsors/carlospolop)!
* **Sluit aan by die** 💬 [**Discord groep**](https://discord.gg/hRep4RUj7f) of die [**telegram groep**](https://t.me/peass) of **volg** ons op **Twitter** 🐦 [**@hacktricks\_live**](https://twitter.com/hacktricks\_live)**.**
* **Deel hacking truuks deur PRs in te dien na die** [**HackTricks**](https://github.com/carlospolop/hacktricks) en [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.

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