How to Block Shell Code Injection & Exploits in Android & iOS Apps
Learn to Block Shell Code Injection in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.
What is Shell Code Injection?
Shell code injection is an attack method where attackers place binary code into a running application, which the application then executes during the process of transferring the app’s user-entered data into the system shell. Attackers can use such exploits to gain access to the data within an app or to change the app’s behavior.
How does Appdome block shell code injection?
Appdome’s Block Shell Code feature prevents malicious programs from injecting modules known as shell code into Android and iOS applications and also prevents shell code from executing inside the app.
Prerequisites for Using Block Shell Code:
To use Appdome’s mobile app security build system to Block Shell Code Injection , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Block Shell Code
- Mobile App (.ipa for iOS, or .apk or .aab for Android)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
Block Shell Code Injection on Mobile apps using Appdome
On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Block Shell Code Injection 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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Block Shell Code Compatible With: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
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Build the feature: Block Shell Code.
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Building Block Shell Code by using Appdome’s DEV-API:
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Create and name the Fusion Set (security template) that will contain the Block Shell Code feature as shown below:
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Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Block Shell Code feature via Appdome Console, to add the Block Shell Code 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 Block Shell Code 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 Block Shell Code feature via Appdome Console
To build the Block Shell Code protection by using Appdome Console, follow the instructions below.
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Where: Inside the Appdome Console, go to Build > Anti Fraud Tab > Mobile Malware Prevention section.
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How: Check whether is toggled On (enabled), otherwise enable it . The feature Block Shell Code is enabled by default, as shown below. Toggle (turn ON) Block Shell Code, 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 Blocks Shell Code Injection.Figure 3: Block Shell Code Injection 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 Block Shell Code you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Block Shell Code
Figure 4: Fusion Set that displays the newly added Block Shell Code protection
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Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Block Shell Code:
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Threat-Events™ OFF > In-App Defense
If the Threat-Events™ setting is cleared (not selected). Appdome will detect and defend the user and app by enforcing Block Shell Code Injection.
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Threat-Events™ ON > In-App Detection
When this setting is used, Appdome detects Shell Code is being injected into the app and passes Appdome’s Threat-Event™ attack intelligence to the app’s business logic for processing, enforcement, and user notification. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ for Block Shell Code Intelligence and Control in Mobile Apps.
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Threat-Events™ ON > In-App Defense
When this setting is used, Appdome detects and defends against Shell Code Injection (same as Appdome Enforce) and passes Appdome’s Threat-Event™ attack intelligence the app’s business logic for processing. For more information on consuming and using Appdome Threat-Events™ in the app, see section Using Threat-Events™ for Block Shell Code Intelligence and Control in Mobile Apps.
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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 Block Shell Code protection is now added to the mobile app -
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Certify the Block Shell Code feature in Mobile Apps
After building Block Shell Code, Appdome generates a Certified Secure™ certificate to guarantee that the Block Shell Code protection has been added and is protecting the app. To verify that the Block Shell Code 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 Block Shell Code has been added to each Mobile app. Certified Secure provides instant and in-line DevSecOps compliance certification that Block Shell Code and other mobile app security features are in each build of the mobile app
Using Threat-Events™ for Shell Code Injection Intelligence and Control in Mobile Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Shell Code Injection is detected. To consume and use Threat-Events™ for Shell Code Injection in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Shell Code Injection shown below.
The specifications and options for Threat-Events™ for Shell Code Injection are:
Threat-Event™ Elements | Block Shell Code Injection Method Detail |
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Appdome Feature Name | Block Shell Code |
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 | |
Visible in ThreatScope™ | |
Developer Parameters for Blocking Shell Code Injection Threat-Event™ | |
Threat-Event NAME | InjectedShellCodeDetected |
Threat-Event DATA | reasonData |
Threat-Event CODE | reasonCode |
Threat-Event REF | 6925 |
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 |
reason | Reason for the detection |
data | Data related to the detection |
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 Shell Code Injection is detected.
The following is a code sample for native Mobile apps, which uses all values in the specification above for Block Shell Code:
x
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("InjectedShellCodeDetected");
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("InjectedShellCodeDetected")
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("InjectedShellCodeDetected"), 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: @"InjectedShellCodeDetected" 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(
"InjectedShellCodeDetected",
(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("InjectedShellCodeDetected"));
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)"InjectedShellCodeDetected", // 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("InjectedShellCodeDetected", 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 = 'InjectedShellCodeDetected'; // 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 Block Shell Code. 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 Block Shell Code
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 Block Magisk & Magisk Root in Android Apps
- How to detect OS Remount in Android
- How to Block Frida Instrumentation Exploits in Android & iOS apps
- How to Privately Code Sign Sealed iOS Apps
- How to Block Frida Instrumentation Exploits in Android & iOS apps
- Testing Anti Remote Desktop Control for iOS in Zoom
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.