How to Enforce Minimum TLS Version, Prevent TLS/SSL Attacks in Android & iOS Apps

Last updated October 20, 2024 by Appdome

This Knowledge Base article describes how to use Appdome’s AI/ML in your CI/CD pipeline to continuously deliver plugins that Block connections using TLS version lower than 1.2 in Mobile apps.

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 Appdome's Enforce TLS Version Plugins:

To use Appdome’s mobile app security build system to Block connections using TLS version lower than 1.2 , you’ll need:

How to Implement Block connections using TLS version lower than 1.2 in 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:

  1. Designate the Mobile App to be protected.

    1. Upload an app via the Appdome Mobile Defense platform GUI or via Appdome’s DEV-API or CI/CD Plugins.

    2. Mobile App Formats: .ipa for iOS, or .apk or .aab for Android
    3. Enforce TLS Version is compatible with: Obj-C, Java, JS, C#, C++, Swift, Kotlin, Flutter, React Native, Unity, Xamarin, and more.
  2. Select the defense: Enforce TLS Version.

      1. Create and name the Fusion Set (security template) that will contain the Enforce TLS Version feature as shown below:
        fusion set that contains Enforce TLS Version .

        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).

      2. Follow the steps in Sections 2.2-2.2.2 of this article to add the Enforce TLS Version feature to your Fusion Set via the Appdome Console.

      3. When you select the Enforce TLS Version you'll notice that the Fusion Set you created in step 2.1 now bears the icon of the protection category that contains Enforce TLS Version.

        Fusion Set applied Enforce TLS Version

        Figure 2: Fusion Set that displays the newly added Enforce TLS Version protection
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      4. 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): fusion Set Detail Summary image

        Figure 3: Fusion Set Detail Summary

      5. Follow the instructions below to use the Fusion Set ID inside any standard mobile DevOps or CI/CD toolkit like Bitrise, Jenkins, Travis, Team City, Circle CI or other system:
        1. Refer to the Appdome API Reference Guide for API building instructions.
        2. Look for sample APIs in Appdome’s GitHub Repository.
    1. Add the Enforce TLS Version feature to your security template.

      1. Navigate to Build > Security tab > Secure Communication section in the Appdome Console.
      2. Toggle On > Enforce TLS Version.

        (a) Choose to monitor this attack vector by checking the Threat Events checkbox associated with Enforce TLS Version as shown below.

        (b) To receive mobile Threat Monitoring, check the ThreatScope™ box as shown below. For more details, see our knowledge base article on ThreatScope™ Mobile XDR.
        Enforce TLS Version option

        Figure 4: Selecting Block connections using TLS version lower than 1.2

        Note: The Appdome Platform displays the Mobile Operation Systems supported by each defense in real-time. For more details, see our OS Support Policy KB.

      3. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Enforce TLS Version:
        1. Threat-Events™ OFF > In-App Defense

          If the Threat-Events™ setting is not selected. Appdome will detect and defend the user and app by enforcing connections using TLS version lower than 1.2.

        2. 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™ to Enforce TLS VersionBlock Intelligence and Control in Mobile Apps.

        3. 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 to 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 VersionBlock Intelligence and Control in Mobile Apps.

      4. Configure the User Experience Options for Enforce TLS Version:
        With Threat-Events™ OFF, Appdome provides several user experience options for mobile brands and developers.
        1. App Compromise Notification: Customize the pop-up or toast Appdome uses to notify the user when a threat is present while using the protected mobile app.
        2. Short message Option. This is available for mobile devices that allow a banner notification for security events.
        3. Localized Message Option. Allows Appdome users to support global languages in security notifications.

          Localized Message

          Figure 5: Default User Experience Options for Appdome’s connections using TLS version lower than 1.2

        4. Enforce TLS Version Threat Code™. Appdome uses AI/ML to generate a unique code each time Enforce TLS Version is triggered by an active threat on the mobile device. Use the code in Appdome Threat Resolution Center™ to help end users identify, find and resolve active threats on the personal mobile devices.
    2. Initiate the build command either by clicking Build My App at the bottom of the Build Workflow (shown in Figure 4) or via your CI/CD as described in Section 2.1.4.
    Congratulations!  The Enforce TLS Version protection is now added to the mobile app
  3. 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: Enforce TLS Version shown in Certificate secure

    Figure 6: 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
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
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.



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:

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.

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