How to Detect PlankFilza File System Tool, Protect iOS Apps

Last updated August 28, 2023 by Appdome

Learn to Detect PlankFilza in iOS apps, in mobile CI/CD with a Data-Driven DevSecOps™ build system.

What is PlankFilza?

PlankFilza is an iOS utility or ‘tweak’ that allows access to the iOS file system/manager. Even though PlankFilza does not require the phone to be jailbroken, it is most often used in combination with Jailbreaking. This combination is used because the elevated level of privileges Jailbreaking provides enables the attacker to compromise the target app much more easily.

PlankFilza works by taking advantage of an exploit in iOS, in order to get limited read/write permissions to the iOS file system of non-jailbroken iOS devices. Once PlankFilza is installed, you can read files from any directory and write to the /var and/tmp locations.

Why Detect PlankFilza in iOS Apps?

While PlankFilza does not provide the wide range of exploits that full-fledged jailbreak techniques provide, it is still an extremely dangerous and potent challenge for security professionals. The fact that PlankFilza is often used in combination with jailbreaking is another significant reason for blocking this utility, and therefore Appdome blocks PlankFilza as part of the protection provided by enabling the Detect Jailbreak feature.

Detect PlankFilza on iOS apps using Appdome

On Appdome, follow these 3 simple steps to create self-defending iOS Apps that Detect PlankFilza without an SDK or gateway:

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. iOS Formats: .ipa
4. Jailbreak Detection Compatible With: Obj-C, C+, Java, Swift, Flutter, React Native, Unity, Xamarin, Cordova and more
Build the feature: Jailbreak Detection.
1. Building Jailbreak Detection by using Appdome’s DEV-API:
  1. Create and name the Fusion Set (security template) that will contain the Jailbreak Detection feature as shown below:
  2. Follow the steps in Sections 2.2.1-2.2.2 of this article, Building the Jailbreak Detection feature via Appdome Console, to add the Jailbreak Detection feature to this Fusion Set.
  3. 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):
    
    Figure 2: Fusion Set Detail Summary
    Note: Annotating the Fusion Set to identify the protection(s) selected is optional only (not mandatory).
  4. 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:
    
    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
2. Building the Jailbreak Detection feature via Appdome Console
  
  To build the Jailbreak Detection protection by using Appdome Console, follow the instructions below.
  1. Where: Inside the Appdome Console, go to Build > Security Tab > OS Integrity section
  2. How: Toggle (turn ON) Jailbreak Detection, 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 Detects PlankFilza.
    
    Figure 3: Detect PlankFilza 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.
  3. When you select the Jailbreak Detection you'll notice that your Fusion Set you created in step 2.1.1 now bears the icon of the protection category that contains Jailbreak Detection
    
    Figure 4: Fusion Set that displays the newly added Jailbreak Detection protection
  4. Select the Threat-Event™ in-app mobile Threat Defense and Intelligence policy for Jailbreak Detection:
    
    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 Detect PlankFilza.
    
    Threat-Events™ ON > In-App Detection
    When this setting is used, Appdome detects that iOS has been compromised via jailbreaking 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 Jailbreak Detection Intelligence and Control in Mobile Apps.
    
    Threat-Events™ ON > In-App Defense
    When this setting is used, Appdome detects and defends against PlankFilza (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 Jailbreak Detection Intelligence and Control in Mobile Apps.
  5. Click Build My App at the bottom of the Build Workflow (shown in Figure 3).
Congratulations! The Jailbreak Detection protection is now added to the mobile app
Certify the Jailbreak Detection feature in iOS Apps.

After building Jailbreak Detection, Appdome generates a Certified Secure™ certificate to guarantee that the Jailbreak Detection protection has been added and is protecting the app. To verify that the Jailbreak Detection 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 Jailbreak Detection has been added to each iOS app. Certified Secure provides instant and in-line DevSecOps compliance certification that Jailbreak Detection and other mobile app security features are in each build of the mobile app

Using Threat-Events™ for PlankFilza Intelligence and Control in iOS Apps

Appdome Threat-Events™ provides consumable in-app mobile app attack intelligence and defense control when PlankFilza is detected. To consume and use Threat-Events™ for PlankFilza in iOS Apps, use AddObserverForName in Notification Center, and the code samples for Threat-Events™ for PlankFilza shown below.

The specifications and options for Threat-Events™ for PlankFilza are:

Threat-Event™ Elements	Detect PlankFilza Method Detail
Appdome Feature Name	Jailbreak Detection
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 Detecting PlankFilza Threat-Event™
Threat-Event NAME	JailbrokenDevice
Threat-Event DATA	reasonData
Threat-Event CODE	reasonCode
Threat-Event REF	6901
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
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
deviceID	Current device ID
reasonCode	Reason code of the occured event
buildDate	Appdome fusion date of the current application
devicePlatform	OS name of the current device
carrierName	Carrier name of the current device
updatedOSVersion	Is the OS version up to date
timeZone	Time zone
deviceFaceDown	Is the device face down
locationLong	Location long
locationLat	Location lat
locationState	Location state
wifiSsid	Wifi SSID
wifiSsidPermissionStatus	Wifi SSID permission status
internalError	Internal error code as hex
extendedMessageText	Internal error code
rInternalErrorCode	Internal error code
reason	Reason for the root detection

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 PlankFilza is detected.

The following is a code sample for native iOS apps, which uses all values in the specification above for Jailbreak Detection:

let center = NotificationCenter.default
                center.addObserver(forName: Notification.Name("JailbrokenDevice"), 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...)
                }

                         
                        Swift
                    
​x
 
let center = NotificationCenter.default
center.addObserver(forName: Notification.Name("JailbrokenDevice"), 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:  "JailbrokenDevice" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
                    __block NSNotification *note = org_note;
                    dispatch_async(dispatch_get_main_queue(), ^(void) {
                        var threatEventsScore = intent.getStringExtra("threatEventsScore")
                        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...)
                    });
                }];

                         
                        Native iOS
                    
​x
 
[[NSNotificationCenter defaultCenter] addObserverForName:  @"JailbrokenDevice" object:nil queue:nil usingBlock:^(NSNotification *org_note) {
    __block NSNotification *note = org_note;
    dispatch_async(dispatch_get_main_queue(), ^(void) {
        var threatEventsScore = intent.getStringExtra("threatEventsScore") 
        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(
                        "JailbrokenDevice",
                        (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...)
                    );
                }

                     
                    React Native
                
​x
 
const { ADDevEvents } = NativeModules;
const aDDevEvents = new NativeEventEmitter(ADDevEvents);
​
function registerToDevEvent(action, callback) {
    NativeModules.ADDevEvents.registerForDevEvent(action);
    aDDevEvents.addListener(action, callback);
}
​
export function registerToAllEvents() {
    registerToDevEvent(
        "JailbrokenDevice",
        (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("JailbrokenDevice"));
                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...)
                }
                }

                    
                    Xamarin/MAUI Android
                
​x
 
RegisterReceiver(new ThreatEventReceiver(), new IntentFilter("JailbrokenDevice"));
​
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)"JailbrokenDevice", // 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(""); // Any other event specific context key
                        // Your logic goes here (Send data to Splunk/Dynatrace/Show Popup...)
                    });

                    
                    Xamarin/MAUI iOS
                
 
NSNotificationCenter.DefaultCenter.AddObserver(
  (NSString)"JailbrokenDevice", // 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("JailbrokenDevice", 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...)
            });

                    
                    Cordova
                
​x
 
window.broadcaster.addEventListener("JailbrokenDevice", 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...)
});

Prerequisites to Using Jailbreak Detection:

To use Appdome’s mobile app security build system to Detect PlankFilza , you’ll need:

Appdome account (create a free Appdome account here)
A license for Jailbreak Detection
Mobile App (.ipa For iOS)
Signing Credentials (see Signing Secure Android apps and Signing Secure iOS apps)

Using Appdome, there are no development or coding prerequisites to build secured iOS Apps by using Jailbreak Detection. 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 Jailbreak Detection

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.

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

How to Detect PlankFilza File System Tool, Protect iOS Apps

What is PlankFilza?

Why Detect PlankFilza in iOS Apps?

Detect PlankFilza on iOS apps using Appdome

Upload the Mobile App to Appdome.

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

Build the feature: Jailbreak Detection.

Building Jailbreak Detection by using Appdome’s DEV-API:

Building the Jailbreak Detection feature via Appdome Console

Certify the Jailbreak Detection feature in iOS Apps.

Using Threat-Events™ for PlankFilza Intelligence and Control in iOS Apps

Prerequisites to Using Jailbreak Detection:

Related Articles:

Thank you!