Info Obfuscated methods

Description

Obfuscation refers to methods to obscure code and make it hard to understand. Compiled Java classes can be decompiled if there is no obfuscation during compilation step.

Adversaries can steal code and repurpose it and sell it in a new application or create a malicious fake application based on the initial one.

Code obfuscation only slows the attacker from reverse engineering but does not make it impossible.

Recommendation

Design the application to add the following protections and slow reverse engineering of the application:

  • Obfuscate Java source code with tools like Proguard or Dexguard
  • buildTypes {
            release {
                minifyEnabled true
                proguardFiles getDefaultProguardFile('proguard-android.txt'),
                'proguard-rules.pro'
            }
        }
  • Verification application signing certificate during runtime by checking context.getPackageManager().signature
  • Check application installer to ensure it matches the Android Market by calling context.getPackageManager().getInstallerPackageName
  • Check running environment at runtime
  • private static String getSystemProperty(String name) throws Exception {
        Class systemPropertyClazz = Class.forName("android.os.SystemProperties");
        return (String) systemPropertyClazz.getMethod("get", new Class[] { String.class }).invoke(systemPropertyClazz, new Object[] { name });
    }
    
    public static boolean checkEmulator() {
    
        try {
            boolean goldfish = getSystemProperty("ro.hardware").contains("goldfish");
            boolean qemu = getSystemProperty("ro.kernel.qemu").length() > 0;
            boolean sdk = getSystemProperty("ro.product.model").equals("sdk");
    
            if (qemu || goldfish || sdk) {
                return true;
            }
    
        } catch (Exception e) {
        }
    
        return false;
      }
  • Check debug flag at runtime
  • context.getApplicationInfo().applicationInfo.flags & ApplicationInfo.FLAG_DEBUGGABLE;

Technical details
PackageObfuscated
okio False
bolts True
android.support.transition True
com.a.a True
com.vnpay.ncb True
android.support.a True
com.crashlytics.android False
android.support.multidex True
okhttp3 False
butterknife True
com.nostra13.socialsharing True
com.vnpay.ticketlib False
com.vnpay.qr True
com.vnpay.vexemphim True
android.support.d True
com.vn.a True
com.google.zxing True
com.viewpagerindicator True
android.support.v4 False
android.os False
android.support.f True
android.support.c True
com.facebook True
android.arch.lifecycle True
com.edmodo.cropper True
com.squareup.picasso True
net.appkraft.parallax True
com.vnpay.notification True
com.chilkatsoft True
com.google.gson False
android.arch.a True
com.vnpay.b True
com.vnpay.vntalk True
android.support.b True
com.google.firebase True
com.vnpay.a True