Running a Checksum Validation of Android & iOS Apps
Learn to Validate Checksum in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.
What is Checksum?
A checksum, otherwise known as “hash”, is a sequence of numbers and letters used for checking data for errors. A checksum is produced by running a program that puts the original file through an algorithm such as MD5, SHA-1, and SHA-256/512. By executing a cryptographic hash function, the algorithm produces the checksum as an input of a fixed length.
Why Should Developers use Checksum Validation??
A checksum validation is used when you received a file and would like to verify that the original file has not been modified or tampered with. If you know the checksum of the original file, running a checksum validation that results in a checksum of the same length proves that no changes were made to your copy. Any change made to the original file, be it one character or one digit, will result in producing an entirely different checksum.
Prerequisites for Using Checksum Validation:
To use Appdome’s mobile app security build system to Validate Checksum , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Checksum Validation
- Mobile App (.ipa for iOS, or .apk or .aab for Android)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
Validate Checksum on Mobile apps using Appdome
On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Validate Checksum without an SDK or gateway:
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Upload the Mobile App to Appdome.
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Upload an app to Appdome’s Mobile App Security Build System
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Upload Method: Appdome Console or DEV-API
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Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
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Checksum Validation Compatible With: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
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Build the feature: Checksum Validation.
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Building Checksum Validation by using Appdome’s DEV-API:
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Create and name the Fusion Set (security template) that will contain the Checksum Validation feature as shown below:
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Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Checksum Validation feature via Appdome Console, to add the Checksum Validation feature to this Fusion Set.
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Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set. Copy the Fusion Set ID from the Fusion Set Detail Summary (as shown below):
Figure 2: Fusion Set Detail Summary
Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory). -
Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, App Center, Jenkins, Travis, Team City, Circle CI or other system:
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Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
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Look for sample APIs in Appdome’s GitHub Repository
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Figure 1: Fusion Set that will contain the Checksum Validation feature
Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required). -
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Building the Checksum Validation feature via Appdome Console
To build the Checksum Validation protection by using Appdome Console, follow the instructions below.
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Where: Inside the Appdome Console, go to Build > Security Tab > ONEShield™ section.
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How: Check whether is toggled On (enabled), otherwise enable it . The feature Checksum Validation is enabled by default, as shown below. Toggle (turn ON) Checksum Validation, as shown below.
If needed, Customize the Threat Notification to be displayed to the mobile end-user in a standard OS dialog notification when Appdome Validates Checksum.Figure 3: Validate Checksum option
Note: The App Compromise Notification contains an easy to follow default remediation path for the mobile app end user. You can customize this message as required to achieve brand specific support, workflow or other messaging. -
When you select the Checksum Validation you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Checksum Validation
Figure 4: Fusion Set that displays the newly added Checksum Validation protection
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Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
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Congratulations! The Checksum Validation protection is now added to the mobile app -
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Certify the Checksum Validation feature in Mobile Apps
After building Checksum Validation, Appdome generates a Certified Secure™ certificate to guarantee that the Checksum Validation protection has been added and is protecting the app. To verify that the Checksum Validation protection has been added to the mobile app, locate the protection in the Certified Secure™ certificate as shown below:
Figure 5: Certified Secure™ certificate
Each Certified Secure™ certificate provides DevOps and DevSecOps organizations the entire workflow summary, audit trail of each build, and proof of protection that Checksum Validation has been added to each Mobile app. Certified Secure provides instant and in-line DevSecOps compliance certification that Checksum Validation and other mobile app security features are in each build of the mobile app
Using Threat-Events™ for Checksum Intelligence and Control in Mobile Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Checksum is detected. To consume and use Threat-Events™ for Checksum in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Checksum shown below.
The specifications and options for Threat-Events™ for Checksum are:
Threat-Event™ Elements | Validate Checksum Method Detail |
---|---|
Appdome Feature Name | Checksum Validation |
Threat-Event Mode | |
OFF, IN-APP DEFENSE | Appdome detects, defends and notifies user (standard OS dialog) using customizable messaging. |
ON, IN-APP DETECTION | Appdome detects the attack or threat and passes the event in a standard format to the app for processing (app chooses how and when to enforce). |
ON, IN-APP DEFENSE | Uses Appdome Enforce mode for any attack or threat and passes the event in a standard format to the app for processing (gather intel on attacks and threats without losing any protection). |
Certified Secure™ Threat Event Check | x |
Visible in ThreatScope™ | x |
Developer Parameters for Validating Checksum Threat-Event™ | |
Threat-Event NAME | |
Threat-Event DATA | reasonData |
Threat-Event CODE | reasonCode |
Threat-Event REF | |
Threat-Event SCORE | |
currentThreatEventScore | Current Threat-Event score |
threatEventsScore | Total Threat-events score |
Threat-Event Context Keys | |
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message | Message displayed for the user on event |
failSafeEnforce | Timed enforcement against the identified threat |
externalID | The external ID of the event which can be listened via Threat Events |
osVersion | OS version of the current device |
deviceModel | Current device model |
deviceManufacturer | The manufacturer of the current device |
fusedAppToken | The task ID of the Appdome fusion of the currently running app |
kernelInfo | Info about the kernel: system name, node name, release, version and machine. |
carrierPlmn | PLMN of the device. Only available for Android devices. |
deviceID | Current device ID |
reasonCode | Reason code of the occurred event |
buildDate | Appdome fusion date of the current application |
devicePlatform | OS name of the current device |
carrierName | Carrier name of the current device. Only available for Android. |
updatedOSVersion | Is the OS version up to date |
deviceBrand | Brand of the device |
deviceBoard | Board of the device |
buildUser | Build user |
buildHost | Build host |
sdkVersion | Sdk version |
timeZone | Time zone |
deviceFaceDown | Is the device face down |
locationLong | Location longitude conditioned by location permission |
locationLat | Location latitude conditioned by location permission |
locationState | Location state conditioned by location permission |
wifiSsid | Wifi SSID |
wifiSsidPermissionStatus | Wifi SSID permission status |
With Threat-Events™ enabled (turned ON), Mobile developers can get detailed attack intelligence and granular defense control in Mobile applications and create amazing user experiences for all mobile end users when Checksum is detected.
The following is a code sample for native Mobile apps, which uses all values in the specification above for Checksum Validation:
x
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("");
BroadcastReceiver threatEventReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String message = intent.getStringExtra("message"); // Message shown to the user
String reasonData = intent.getStringExtra("reasonData"); // Threat detection cause
String reasonCode = intent.getStringExtra("reasonCode"); // Event reason code
String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore"); // Current threat event score
String threatEventsScore = intent.getStringExtra("threatEventsScore"); // Total threat events score
String variable = intent.getStringExtra("<Context Key>"); // Any other event specific context key
​
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
};
​
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED);
} else {
registerReceiver(threatEventReceiver, intentFilter);
}
x
val intentFilter = IntentFilter()
intentFilter.addAction("")
val threatEventReceiver = object : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
var message = intent?.getStringExtra("message") // Message shown to the user
var reasonData = intent?.getStringExtra("reasonData") // Threat detection cause
var reasonCode = intent?.getStringExtra("reasonCode") // Event reason code
var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore") // Current threat event score
var threatEventsScore = intent?.getStringExtra("threatEventsScore") // Total threat events score
var variable = intent?.getStringExtra("<Context Key>") // Any other event specific context key
​
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
}
​
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
registerReceiver(threatEventReceiver, intentFilter, Context.RECEIVER_NOT_EXPORTED)
} else {
registerReceiver(threatEventReceiver, intentFilter)
}
let center = NotificationCenter.default
center.addObserver(forName: Notification.Name(""), object: nil, queue: nil) { (note) in
guard let usrInf = note.userInfo else {
return
}
let message = usrInf["message"]; // Message shown to the user
let reasonData = usrInf["reasonData"]; // Threat detection cause
let reasonCode = usrInf["reasonCode"]; // Event reason code
let currentThreatEventScore = usrInf["currentThreatEventScore"]; // Current threat event score
let threatEventsScore = usrInf["threatEventsScore"]; // Total threat events score
let variable = usrInf["<Context Key>"]; // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
[[NSNotificationCenter defaultCenter] addObserverForName: @"" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
__block NSNotification *note = org_note;
dispatch_async(dispatch_get_main_queue(), ^(void) {
NSString *message = [[note userInfo] objectForKey:@"message"]; // Message shown to the user
NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"]; // Threat detection cause
NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"]; // Event reason code
NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"]; // Current threat event score
NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"]; // Total threat events score
NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"]; // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});
}];
const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
function registerToDevEvent(action, callback) {
NativeModules.ADDevEvents.registerForDevEvent(action);
aDDevEvents.addListener(action, callback);
}
export function registerToAllEvents() {
registerToDevEvent(
"",
(userinfo) => Alert.alert(JSON.stringify(userinfo))
var message = userinfo["message"] // Message shown to the user
var reasonData = userinfo["reasonData"] // Threat detection cause
var reasonCode = userinfo["reasonCode"] // Event reason code
var currentThreatEventScore = userinfo["currentThreatEventScore"] // Current threat event score
var threatEventsScore = userinfo["threatEventsScore"] // Total threat events score
var variable = userinfo["<Context Key>"] // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
);
}
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter(""));
class ThreatEventReceiver : BroadcastReceiver
{
public override void OnReceive(Context context, Intent intent)
{
String message = intent.GetStringExtra("message"); // Message shown to the user
String reasonData = intent.GetStringExtra("reasonData"); // Threat detection cause
String reasonCode = intent.GetStringExtra("reasonCode"); // Event reason code
String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore"); // Current threat event score
String threatEventsScore = intent.GetStringExtra("threatEventsScore"); // Total threat events score
String variable = intent.GetStringExtra("<Context Key>"); // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
}
NSNotificationCenter.DefaultCenter.AddObserver(
(NSString)"", // Threat-Event Identifier
delegate (NSNotification notification)
{
var message = notification.UserInfo.ObjectForKey("message"); // Message shown to the user
var reasonData = notification.UserInfo.ObjectForKey("reasonData"); // Threat detection cause
var reasonCode = notification.UserInfo.ObjectForKey("reasonCode"); // Event reason code
var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore"); // Current threat event score
var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore"); // Total threat events score
var variable = notification.UserInfo.ObjectForKey("<Context Keys>"); // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});
window.broadcaster.addEventListener("", function(userInfo) {
var message = userInfo.message // Message shown to the user
var reasonData = userInfo.reasonData // Threat detection cause
var reasonCode = userInfo.reasonCode // Event reason code
var currentThreatEventScore = userInfo.currentThreatEventScore // Current threat event score
var threatEventsScore = userInfo.threatEventsScore // Total threat events score
var variable = userInfo.<Context Key> // Any other event specific context key
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});
xxxxxxxxxx
import 'dart:async';
​
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
​
class PlatformChannel extends StatefulWidget {
const PlatformChannel({super.key});
​
State<PlatformChannel> createState() => _PlatformChannelState();
}
​
class _PlatformChannelState extends State<PlatformChannel> {
static const String _eventChannelName = ''; // Replace with your EventChannel name
static const EventChannel _eventChannel = EventChannel(_eventChannelName);
​
void initState() {
super.initState();
_eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError);
}
​
void _onEvent(Object? event) {
setState(() {
// Adapt this section based on your specific event data structure
var eventData = event as Map;
​
// Example: Accessing 'externalID' field from the event
var externalID = eventData['externalID'];
​
// Customize the rest of the fields based on your event structure
String message = eventData['message']; // Message shown to the user
String reasonData = eventData['reasonData']; // Threat detection cause
String reasonCode = eventData['reasonCode']; // Event reason code
String currentThreatEventScore = eventData['currentThreatEventScore']; // Current threat event score
String threatEventsScore = eventData['threatEventsScore']; // Total threat events score
​
// Any other event specific context key
String variable = eventData['<Context Key>'];
});
}
​
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
Using Appdome, there are no development or coding prerequisites to build secured Mobile Apps by using Checksum Validation. There is no SDK and no library to code or implement in the app and no gateway to deploy in your network. All protections are built into each app and the resulting app is self-defending and self-protecting.
Releasing and Publishing Mobile Apps with Checksum Validation
After successfully securing your app by using Appdome, there are several available options to complete your project, depending on your app lifecycle or workflow. These include:
- Customizing, Configuring & Branding Secure Mobile Apps
- Deploying/Publishing Secure mobile apps to Public or Private app stores
- Releasing Secured Android & iOS Apps built on Appdome.
Related Articles:
- How To Prevent Tampering of Android & iOS Apps
- How to Block Runtime Code Manipulations in Android & iOS Apps
- How to Block Resigning and Repackaging Android & iOS Apps
- How to Prevent Debuggable Android & iOS Apps in Production
How Do I Learn More?
If you have any questions, please send them our way at support.appdome.com or via the chat window on the Appdome platform.
Thank you!
Thanks for visiting Appdome! Our mission is to secure every app on the planet by making mobile app security easy. We hope we’re living up to the mission with your project.