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

Last updated August 10, 2022 by Appdome

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.

What is connections 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.

Blocking connections using TLS version lower than 1.2 on Mobile apps by 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. Upload the Mobile App to Appdome.

    1. Upload an app to Appdome’s Mobile App Security Build System

    2. Upload Method: Appdome Console or DEV-API
    3. Mobile App Formats: .ipa For iOS device or .apk or .aab
  2. Build the Protection: Enforce TLS Version.

    1. Building Enforce TLS Version by using Appdome’s DEV-API:

      1. Create and name the Fusion Set (security template) that will contain the Enforce TLS Version feature as shown below:
      2. 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).

      3. 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.

      4. Open the Fusion Set Detail Summary by clicking the “...” symbol on the far-right corner of the Fusion Set, as shown in Figure 1 above, and get the Fusion Set ID from the Fusion Set Detail Summary (as shown below): fusion Set Detail Summary image

        Figure 2: Fusion Set Detail Summary
        Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).

      5. 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, Cirlce CI or other system:
        1. Build an API for the app – for instructions, see the tasks under Appdome API Reference Guide
        2. Look for sample APIs in Appdome’s GitHub Repository
    2. Building the Enforce TLS Version feature via Appdome Console

      To build the Enforce TLS Version protection by using Appdome Console, follow the instructions below.

      1. Where: Inside the Appdome Console, go to Build > Security Tab > Secure Communication section
      2. How: Toggle (turn ON) Enforce TLS Version, as shown below. Enforce TLS Version option

        Figure 3: Block connections using TLS version lower than 1.2 option

      3. 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

        Fusion Set applied Enforce TLS Version

        Figure 4: Fusion Set that displays the newly added Enforce TLS Version protection

      4. 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 cleared (not selected). Appdome will detect and defend the user and app by enforcing Block 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™ for Enforce TLS Version 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 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.

      5. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
    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 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
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 DETECTON 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
messageMessage displayed for the user on event
externalIDThe external ID of the event which can be listened via Threat Events
osVersionOS version of the current device
deviceModelCurrent device model
deviceManufacturerThe manufacturer of the current device
fusedAppTokenThe task ID of the Appdome fusion of the currently running app
kernelInfoInfo about the kernel: system name, node name, release, version and machine.
carrierPlmnPLMN of the device
deviceIDCurrent device ID
reasonCodeReason code of the occured event
buildDateAppdome fusion date of the current application
devicePlatformOS name of the current device
carrierNameCarrier name of the current device
updatedOSVersionIs the OS version up to date
deviceBrandBrand of the device
deviceBoardBoard of the device
buildUserBuild user
buildHostBuild host
sdkVersionSdk version
timeZoneTime zone
deviceFaceDownIs the device face down
locationLongLocation long
locationLatLocation lat
locationStateLocation state
wifiSsidWifi SSID
wifiSsidPermissionStatusWifi SSID permission status
hostFailed host
IncompatibleSslVersionCurrent SSL version
DeveventDetailedErrorMessageError message
extendedMessageTextExtended 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:

Prerequisites to 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:

Using Appdome, there are no development or coding prerequisites to build secured 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:

All apps protected by Appdome are fully compatible with any public app store, including Apple App Store, Google Play, Huawei App Gallery and more.

Protections Similar to Enforce TLS Version

Here are a few related resources:

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.

If you have any questions, please send them our way at support.appdome.com or via the chat window on the Appdome platform.

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