How to Enforce Minimum TLS Version, Prevent TLS/SSL Attacks in Android & iOS Apps
Learn to Block connections using TLS version lower than 1.2 in Mobile apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.
Which Connection are Using TLS Version Lower than 1.2?
The TLS/SSL protocol supports a wide range of cryptographic algorithms for establishing a secure communication channel and communicating over it.
Every secure connection begins with a “handshake” during which several parameters of the communication are decided. One of which is the version of the protocol:
- SSL 3.0 (released in 1996)
- TLS 1.0
- TLS 1.1
- TLS 1.2 (released in 2008)
- TLS 1.3 (released in August 2018, not yet fully adopted)
Old versions of the protocol carry some vulnerabilities. Attacks like POODLE and BEAST rely on exploiting weaknesses of older implementations of TLS.In addition, it is not uncommon for attackers to intentionally impersonate servers or weaken their parameters in order to downgrade the security/encryption of a TLS session so that they can attack it more easily.
Why Block connections using TLS version lower than 1.2 in Mobile Apps?
A very effective countermeasure against this class of attacks is to only use a current version or the latest version of TLS. Implementing and especially maintaining such measures is a difficult task. Sometimes the source code is not available, and more often the services are on uncontrolled endpoints.
Appdome Enforce TLS Version ensures that network connections conform to TLS 1.2 version or higher.
Prerequisites for Using Enforce TLS Version:
To use Appdome’s mobile app security build system to Block connections using TLS version lower than 1.2 , you’ll need:
- Appdome account (create a free Appdome account here)
- A license for Enforce TLS Version
- Mobile App (.ipa for iOS, or .apk or .aab for Android)
- Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)
Block connections using TLS version lower than 1.2 on Mobile apps using Appdome
On Appdome, follow these 3 simple steps to create self-defending Mobile Apps that Block connections using TLS version lower than 1.2 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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Enforce TLS Version Compatible With: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more
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Build the feature: Enforce TLS Version.
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Building Enforce TLS Version by using Appdome’s DEV-API:
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Create and name the Fusion Set (security template) that will contain the Enforce TLS Version feature as shown below:
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Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Enforce TLS Version feature via Appdome Console, to add the Enforce TLS Version 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 Enforce TLS Version 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 Enforce TLS Version feature via Appdome Console
To build the Enforce TLS Version protection by using Appdome Console, follow the instructions below.
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Where: Inside the Appdome Console, go to Build > Security Tab > Secure Communication section.
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How: Check whether is toggled On (enabled), otherwise enable it . The feature Enforce TLS Version is enabled by default, as shown below. Toggle (turn ON) Enforce TLS Version, 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 connections using TLS version lower than 1.2.Figure 3: Block connections using TLS version lower than 1.2 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 Enforce TLS Version you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Enforce TLS Version
Figure 4: Fusion Set that displays the newly added Enforce TLS Version protection
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Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Enforce TLS Version:
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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 connections using TLS version lower than 1.2.
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Threat-Events™ ON > In-App Detection
When this setting is used, Appdome detects that the TLS version is lower than 1.2 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 Enforce TLS Version 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 connections using TLS version lower than 1.2 (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 Enforce TLS Version 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 Enforce TLS Version protection is now added to the mobile app -
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Certify the Enforce TLS Version feature in Mobile Apps
After building Enforce TLS Version, Appdome generates a Certified Secure™ certificate to guarantee that the Enforce TLS Version protection has been added and is protecting the app. To verify that the Enforce TLS Version 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 Enforce TLS Version has been added to each Mobile app. Certified Secure provides instant and in-line DevSecOps compliance certification that Enforce TLS Version and other mobile app security features are in each build of the mobile app
Using Threat-Events™ for connections using TLS version lower than 1.2 Intelligence and Control in Mobile Apps
Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when connections using TLS version lower than 1.2 is detected. To consume and use Threat-Events™ for connections using TLS version lower than 1.2 in Mobile Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for connections using TLS version lower than 1.2 shown below.
The specifications and options for Threat-Events™ for connections using TLS version lower than 1.2 are:
Threat-Event™ Elements | Block connections using TLS version lower than 1.2 Method Detail |
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Appdome Feature Name | Enforce TLS Version |
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 connections using TLS version lower than 1.2 Threat-Event™ | |
Threat-Event NAME | SslIncompatibleVersion |
Threat-Event DATA | reasonData |
Threat-Event CODE | reasonCode |
Threat-Event REF | 6502 |
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 |
threatCode | The last six characters of the threat code specify the OS, allowing the Threat Resolution Center to address the attack on the affected device. |
host | The host that failed SSL version validation |
IncompatibleSslVersion | Current SSL version |
DeveventDetailedErrorMessage | Error message |
extendedMessageText | Extended message |
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 connections using TLS version lower than 1.2 is detected.
The following is a code sample for native Mobile apps, which uses all values in the specification above for Enforce TLS Version:
Important! Replace all placeholder instances of <Context Key> with the specific name of your threat event context key across all language examples. This is crucial to ensure your code functions correctly with the intended event data. For example, The <Context Key> could be the message, externalID, OS Version, reason code, etc.
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IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("SslIncompatibleVersion");
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
// Current threat event score
String currentThreatEventScore = intent.getStringExtra("currentThreatEventScore");
// Total threat events score
String threatEventsScore = intent.getStringExtra("threatEventsScore");
// Replace '<Context Key>' with your specific event context key
// String variable = intent.getStringExtra("<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);
}
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val intentFilter = IntentFilter()
intentFilter.addAction("SslIncompatibleVersion")
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
// Current threat event score
var currentThreatEventScore = intent?.getStringExtra("currentThreatEventScore")
// Total threat events score
var threatEventsScore = intent?.getStringExtra("threatEventsScore")
// Replace '<Context Key>' with your specific event context key
// var variable = intent?.getStringExtra("<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
let center = NotificationCenter.default
center.addObserver(forName: Notification.Name("SslIncompatibleVersion"), 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
// Current threat event score
let currentThreatEventScore = usrInf["currentThreatEventScore"];
// Total threat events score
let threatEventsScore = usrInf["threatEventsScore"];
// Replace '<Context Key>' with your specific event context key
// let variable = usrInf["<Context Key>"];
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
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[[NSNotificationCenter defaultCenter] addObserverForName: @"SslIncompatibleVersion" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
__block NSNotification *note = org_note;
dispatch_async(dispatch_get_main_queue(), ^(void) {
// Message shown to the user
NSString *message = [[note userInfo] objectForKey:@"message"];
// Threat detection cause
NSString *reasonData = [[note userInfo] objectForKey:@"reasonData"];
// Event reason code
NSString *reasonCode = [[note userInfo] objectForKey:@"reasonCode"];
// Current threat event score
NSString *currentThreatEventScore = [[note userInfo] objectForKey:@"currentThreatEventScore"];
// Total threat events score
NSString *threatEventsScore = [[note userInfo] objectForKey:@"threatEventsScore"];
// Replace '<Context Key>' with your specific event context key
// NSString *variable = [[note userInfo] objectForKey:@"<Context Key>"];
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});
}];
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const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
function registerToDevEvent(action, callback) {
NativeModules.ADDevEvents.registerForDevEvent(action);
aDDevEvents.addListener(action, callback);
}
export function registerToAllEvents() {
registerToDevEvent(
"SslIncompatibleVersion",
(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
// Current threat event score
var currentThreatEventScore = userinfo["currentThreatEventScore"]
// Total threat events score
var threatEventsScore = userinfo["threatEventsScore"]
// Replace '<Context Key>' with your specific event context key
// var variable = userinfo["<Context Key>"]
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
);
}
x
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("SslIncompatibleVersion"));
class ThreatEventReceiver : BroadcastReceiver
{
public override void OnReceive(Context context, Intent intent)
{
// Message shown to the user
String message = intent.GetStringExtra("message");
// Threat detection cause
String reasonData = intent.GetStringExtra("reasonData");
// Event reason code
String reasonCode = intent.GetStringExtra("reasonCode");
// Current threat event score
String currentThreatEventScore = intent.GetStringExtra("currentThreatEventScore");
// Total threat events score
String threatEventsScore = intent.GetStringExtra("threatEventsScore");
// Replace '<Context Key>' with your specific event context key
// String variable = intent.GetStringExtra("<Context Key>");
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
}
x
NSNotificationCenter.DefaultCenter.AddObserver(
(NSString)"SslIncompatibleVersion", // Threat-Event Identifier
delegate (NSNotification notification)
{
// Message shown to the user
var message = notification.UserInfo.ObjectForKey("message");
// Threat detection cause
var reasonData = notification.UserInfo.ObjectForKey("reasonData");
// Event reason code
var reasonCode = notification.UserInfo.ObjectForKey("reasonCode");
// Current threat event score
var currentThreatEventScore = notification.UserInfo.ObjectForKey("currentThreatEventScore");
// Total threat events score
var threatEventsScore = notification.UserInfo.ObjectForKey("threatEventsScore");
// Replace '<Context Key>' with your specific event context key
// var variable = notification.UserInfo.ObjectForKey("<Context Keys>");
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
}
);
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window.broadcaster.addEventListener("SslIncompatibleVersion", 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
// Current threat event score
var currentThreatEventScore = userInfo.currentThreatEventScore
// Total threat events score
var threatEventsScore = userInfo.threatEventsScore
// Replace '<Context Key>' with your specific event context key
// var variable = userInfo.<Context Keys>
// Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
});
x
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> {
// Replace with your EventChannel name
static const String _eventChannelName = "SslIncompatibleVersion";
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
// Current threat event score
String currentThreatEventScore = eventData['currentThreatEventScore'];
// Total threat events score
String threatEventsScore = eventData['threatEventsScore'];
// Replace '<Context Key>' with your specific event context key
// String variable = eventData['<Context Keys>'];
});
}
// 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 Enforce TLS Version. 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 Enforce TLS Version
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:
You can read about all the properties and features of various TLS versions in Wikipedia.
If you are interested in limiting other aspects of TLS, you should check out how you can Enforce Communications’ Cipher Suites.
This feature is just one of many offered in the course of Trusted Session Inspection.
To zoom out on this topic, visit Appdome for Mobile App Security on our website.
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.