feat: support weblogic filter listener (#5)

vul/vul-webapp/src/main/java/Base64ClassLoaderServlet.java

@@ -0,0 +1,51 @@
+import javax.servlet.*;
+import java.io.IOException;
+
+/**
+ * @author ReaJason
+ * @since 2024/12/24
+ */
+public class Base64ClassLoaderServlet extends ClassLoader implements Servlet {
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+
+    }
+
+    @Override
+    public ServletConfig getServletConfig() {
+        return null;
+    }
+
+    @Override
+    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
+        String data = req.getParameter("data");
+        try {
+            byte[] bytes = decodeBase64(data);
+            defineClass(null, bytes, 0, bytes.length).newInstance();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    static byte[] decodeBase64(String base64Str) throws Exception {
+        try {
+            Class<?> decoderClass = Class.forName("sun.misc.BASE64Decoder");
+            return (byte[]) decoderClass.getMethod("decodeBuffer", String.class).invoke(decoderClass.newInstance(), base64Str);
+        } catch (Exception var4) {
+            Class<?> decoderClass = Class.forName("java.util.Base64");
+            Object decoder = decoderClass.getMethod("getDecoder").invoke((Object) null);
+            return (byte[]) decoder.getClass().getMethod("decode", String.class).invoke(decoder, base64Str);
+        }
+    }
+
+    @Override
+    public String getServletInfo() {
+        return "";
+    }
+
+    @Override
+    public void destroy() {
+
+    }
+}