线上第六期_Android 安全测试_20181013

课前准备

往期参考:https://testerhome.com/topics/16073
OWASP: https://www.owasp.org/index.php/Main_Page
Mobile_App_Security_Checklist: https://github.com/OWASP/owasp-mstg/raw/master/Checklists/Mobile_App_Security_Checklist.xlsx
Jadx: https://github.com/skylot/jadx/releases
Smali: https://source.android.com/devices/tech/dalvik/dalvik-bytecode

逆向分析

jadx

反编译

java -jar apktool_2.3.4.jar d keep_1013.apk  -o keep
vi  /Users/seveniruby/temp/mobile_sec/keep/smali_classes4/com/gotokeep/keep/splash/SplashActivity.smali
mv keep/res/drawable-xxhdpi/bg_top_shadow.png keep/res/drawable-xxhdpi/bg_top_shadow.png.bak
mv keep/res/drawable-xxhdpi/icon_store_pre_sale_current.9.png keep/res/drawable-xxhdpi/icon_store_pre_sale_current.9.png.bak
java -jar apktool_2.3.4.jar b keep -o keep-new.apk

[ -f my-release-key.jks ]  || keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias my-alias
jarsigner -verbose -keystore my-release-key.jks  -signedjar keep-new-signed.apk  keep-new.apk  my-alias
adb install -r keep-new-signed.apk

植入代码

Android Studio Java2Smali插件可以把Java编译为Smali

        Log.i("hogwarts", "onCreate "+ System.currentTimeMillis());

smali指令为

    const-string v1, "hogwarts"
    new-instance v2, Ljava/lang/StringBuilder;
    invoke-direct {v2}, Ljava/lang/StringBuilder;-><init>()V
    const-string v3, "onCreate "
    invoke-virtual {v2, v3}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;
    move-result-object v2
    invoke-static {}, Ljava/lang/System;->currentTimeMillis()J
    move-result-wide v4
    invoke-virtual {v2, v4, v5}, Ljava/lang/StringBuilder;->append(J)Ljava/lang/StringBuilder;
    move-result-object v2
    invoke-virtual {v2}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;
    move-result-object v2
    invoke-static {v1, v2}, Landroid/util/Log;->i(Ljava/lang/String;Ljava/lang/String;)I
System.out.println("hogwarts");

smali指令为

const-string v0, "testerhome"
const-string v1, "hello from seveniruby"
invoke-static {v0, v1}, Landroid/util/Log;->e(Ljava/lang/String;Ljava/lang/String;)I

寄存器数量需要根据编译出来的代码做调整,一般尽量修为该比较大的值,比如8

xposed

hook后


package com.testerhome.appium.xposeddemo1013;

import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;
import android.graphics.Color;
import android.widget.TextView;
import de.robv.android.xposed.IXposedHookLoadPackage;
import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.callbacks.XC_LoadPackage.LoadPackageParam;

public class RedClock implements IXposedHookLoadPackage {
    public void handleLoadPackage(LoadPackageParam lpparam) throws Throwable {
        if (!lpparam.packageName.equals("com.android.systemui"))
            return;

        findAndHookMethod("com.android.systemui.statusbar.policy.Clock", lpparam.classLoader, "updateClock", new XC_MethodHook() {
            @Override
            protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                TextView tv = (TextView) param.thisObject;
                String text = tv.getText().toString();
                tv.setText(text + "hogwarts 6th :)");
                tv.setTextColor(Color.RED);
            }
        });
    }
}
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