How to Obfuscate Dynamically Loaded Symbols in iOS Apps
Learn to Obfuscate Dynamically Loaded Symbols in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.
What are Dynamically Loaded Symbols?
Dynamically Loaded Symbols, commonly known as Lazy symbols, are symbols found in iOS binaries (Mach-O format). These symbols are imported from other binaries or dynamically linked libraries, be they from the system or third-party sources, yet they aren’t implemented directly within the binary. Every binary might contain lazy symbols from various libraries. What sets lazy symbols apart is their addressing; Their final address is determined only when the app first tries to use them upon loading. In contrast, all other imported symbols have their addresses resolved during the app’s initial launch, rather than at first use. The responsibility for resolving these imported symbols and identifying their addresses falls to the dyld, the dynamic linker component of iOS.
Why It's Necessary to Obfuscate Dynamically Loaded Symbols?
Obfuscating Dynamically Loaded Symbols is vital, especially in the context of defending against static analysis by reversers. Through static analysis, reversers can meticulously extract detailed information about the symbols an app imports. A particular area of concern is the unveiling of cryptographic functions, such as MD5 or SHA256, that the app might be leveraging from system libraries or third-party sources. By discerning which cryptographic methods are in play, reversers not only gain hints about decrypting secured data but also establish a precise anchor pinpointing where and when these functions come into action. Armed with this insight, they can potentially manipulate the app in real-time, disabling or even altering the intended purpose of these imported functions. Given these significant threats, obfuscation stands as not just a protective measure but an imperative shield, ensuring that the app remains inscrutable, safeguarding its intellectual property, data, and overall functionality from potentially disastrous tampering.
Prerequisites for Using Obfuscate Dynamically Loaded Symbols:
To use Appdome’s mobile app security build system to Obfuscate Dynamically Loaded Symbols , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Obfuscate Dynamically Loaded Symbols
- Mobile App (.ipa for iOS)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
Obfuscate Dynamically Loaded Symbols on iOS apps using Appdome
On Appdome, follow these simple steps to create self-defending iOS Apps that Obfuscate Dynamically Loaded Symbols without an SDK or gateway:
-
Upload the Mobile App to Appdome.
-
Upload an app to Appdome’s Mobile App Security Build System
-
Upload Method: Appdome Console or DEV-API
-
iOS Formats: .ipa
-
Obfuscate Dynamically Loaded Symbols Compatible With: Obj-C, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and more
-
-
Build the feature: Obfuscate Dynamically Loaded Symbols.
-
Building Obfuscate Dynamically Loaded Symbols by using Appdome’s DEV-API:
-
Create and name the Fusion Set (security template) that will contain the Obfuscate Dynamically Loaded Symbols feature as shown below:
-
Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Obfuscate Dynamically Loaded Symbols feature via Appdome Console, to add the Obfuscate Dynamically Loaded Symbols feature to this Fusion Set.
-
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:
-
Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
-
Look for sample APIs in Appdome’s GitHub Repository
-
Figure 1: Fusion Set that will contain the Obfuscate Dynamically Loaded Symbols feature
Note: Naming the Fusion Set to correspond to the protection(s) selected is for illustration purposes only (not required). -
-
Building the Obfuscate Dynamically Loaded Symbols feature via Appdome Console
To build the Obfuscate Dynamically Loaded Symbols protection by using Appdome Console, follow the instructions below.
-
Where: Inside the Appdome Console, go to Build > Security Tab > TOTALCode™ Obfuscation section.
-
How: Check whether Binding Obfuscation is toggled On (enabled), otherwise enable it . The feature Obfuscate Dynamically Loaded Symbols is enabled by default, as shown below. Toggle (turn ON) Obfuscate Dynamically Loaded Symbols, as shown below.
Figure 3: Obfuscate Dynamically Loaded Symbols option
-
When you enable Binding Obfuscation you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Obfuscate Dynamically Loaded Symbols
Figure 4: Fusion Set that displays the newly added Obfuscate Dynamically Loaded Symbols protection
-
Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
-
Congratulations! The Obfuscate Dynamically Loaded Symbols protection is now added to the mobile app -
-
Certify the Obfuscate Dynamically Loaded Symbols feature in iOS Apps
After building Obfuscate Dynamically Loaded Symbols, Appdome generates a Certified Secure™ certificate to guarantee that the Obfuscate Dynamically Loaded Symbols protection has been added and is protecting the app. To verify that the Obfuscate Dynamically Loaded Symbols 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 Obfuscate Dynamically Loaded Symbols has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Obfuscate Dynamically Loaded Symbols and other mobile app security features are in each build of the mobile app
Using Threat-Events™ for Dynamically Loaded Symbols Intelligence and Control in iOS Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when Dynamically Loaded Symbols is detected. To consume and use Threat-Events™ for Dynamically Loaded Symbols in iOS Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for Dynamically Loaded Symbols shown below.
The specifications and options for Threat-Events™ for Dynamically Loaded Symbols are:
Threat-Event™ Elements | Obfuscate Dynamically Loaded Symbols Method Detail |
---|---|
Appdome Feature Name | Obfuscate Dynamically Loaded Symbols |
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 Obfuscating Dynamically Loaded Symbols 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 | |
---|---|
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. |
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 |
updatedOSVersion | Is the OS version up to date |
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), iOS developers can get detailed attack intelligence and granular defense control in iOS applications and create amazing user experiences for all mobile end users when Dynamically Loaded Symbols is detected.
The following is a code sample for native iOS apps, which uses all values in the specification above for Obfuscate Dynamically Loaded Symbols:
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 iOS Apps by using Obfuscate Dynamically Loaded Symbols. 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 Obfuscate Dynamically Loaded Symbols
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:
- iOS Binding Obfuscation, Anti-Reversing in iOS App
- Binary Code Obfuscation, Anti-Reversing Android & iOS
- Non-Native Code Obfuscation, Anti-Reversing for Android & iOS Frameworks
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.