Mobile VPN leaks can expose your IP address and other information. They’re usually caused by connectivity checks run by apps in the background.
VPN leaks may allow malicious parties to find information about your browsing activity, your device, and even yourself. ISPs, for instance, can view all your traffic, as well as the device you’re using.
You can identify mobile VPN leaks using a Rasperry Pi, OpenWRT, and Wireshark. Once you identify whether your mobile VPN is leaking or not, you can then fix it using Android debug bridge (adb) on Android and Windows.
In case your VPN leak is caused by your mobile OS, which is highly likely, there are some (easy) fixes you can try, such as:
- Using airplane mode to stop processes that started before you turned on your VPN
- Disabling connectivity checks on Android using Android debug bridge (adb)
- Getting a VPN router to protect all your data traffic on any device
The best VPN you can use to prevent the risk of a mobile VPN leak is to use NordVPN. It offers AES 256-bit encryption, and ensures that your traffic is fully encrypted before passing through the encryption tunnel.
To learn more about these fixes and our method for detecting mobile VPN leaks, check out the complete article below.
Mobile VPN use is becoming increasingly common, as it allows users to protect themselves online, while also unblocking content. A VPN protects your privacy, keeping your data safe from hackers, data brokerages, and intrusive advertising cookies.
However, there’s always the risk of a mobile VPN leak that could expose your data. This could prove to be serious, and malicious actors may end up stealing your personal information. Depending on your online activities, this could pose some serious danger.
Understanding mobile VPN leaks and the dangers that they pose is important, as it allows you to take steps to protect yourself and keep your identity safe.
What is a Mobile VPN leak?
A mobile VPN leak occurs when your VPN fails to properly pass your connection through an encryption tunnel, thus exposing your IP address, DNS requests, or browsing activity. ISPs, government trackers, or data harvesters might be able to access your information in this case.
This can prove to be a serious issue, especially if you’re visiting a prohibited site, or are in a country that that prohibits VPN use, such as China. If you’re sharing sensitive information, a VPN leak could expose your identity.
What causes a mobile VPN leak on Android?
You’d be surprised to know that a mobile VPN leak isn’t always caused by an issue with your VPN. In some cases, a mobile VPN leak might occur because of the operating system you use it on.
On Android, for instance, the issue arises from a built-in OS feature: connectivity checks. These checks consist of small, automated data transfers. These small “data packages” provide applications with network connectivity information about your device.
Essentially, connectivity checks allow apps running in the background, such as social media apps or messaging apps, to check whether you’re connected to the internet. This is an important requirement, since it allows apps to send out push notifications at the correct time.
If you’re not always connected to a VPN on your phone, these connectivity checks can end up revealing personal information about your device.
For instance, if you have a browser tab open in the background, and turn off your VPN, a connectivity check may end up revealing accurate information about your connection. In extreme cases, this could prove to be serious too.
What causes a mobile VPN leak on iOS?
Just like Android, iOS has some inherent issues that can cause VPN leaks. These can be summarized as follows:
- Processes that started before you enable your VPN can continue sending data outside of your VPN tunnel.
- Certain third-party apps can bypass the VPN tunnel and see your real IP address.
- Some Apple services can bypass your VPN connection altogether.
The Dangers of a Mobile VPN Leak
A leaking VPN connection can lead to some serious privacy and security disasters, such as the ones below.
Hackers and malicious parties tracking your unencrypted traffic
This is probably the worst-case scenario as far as VPN leaks go. As mentioned, some apps may completely bypass your VPN connection, especially internal operating system processes. This obviously poses a major security risk, especially if you’re on a public network.
This means malicious parties on the same network, such as hackers, can see all your traffic. In case you’re accessing a banned website, this could land you in trouble. Similarly, someone with malicious intent could track your browsing activity, which poses a serious privacy risk.
(Malicious) parties finding out your IP, DNS requests, and other information
Fortunately, VPNs encrypt your data before transmission. Therefore, if a VPN leak causes your traffic to “merely” bypass your VPN tunnel, it’s still going to be encrypted and not easily readable.
However, malicious parties can still use this information to gather information about you, such as your approximate location or your device type. If another app leaks more information, your real IP address might be exposed too.
Moreover, in the case of a DNS leak, your DNS queries will go straight to your internet service provider. That is to say, instead of your VPN relaying your DNS requests to their own DNS servers.
As a result, your ISP will be able to track your browsing activity. In certain countries, such as China, they could relay this information to the government too.
Mobile VPN Leak Test: Using a Raspberry Pi, OpenWRT, and Wireshark
Spotting a mobile VPN leak can often be a bit more difficult than its desktop equivalent, since only a few apps might be transmitting data outside the VPN tunnel. This means that doing a regular DNS leak test or WebRTC leak test in your browser (which is just one app) might not cut it.
We’ll discuss a VPN leak test in this article that has a much better chance of detecting mobile VPN leaks. This method requires a Raspberry Pi, Linux’s OpenWRT distribution, and Wireshark, a network protocol analyzer.
Essentially, the aim is to use your Raspberry Pi and OpenWRT to act as a “bridge” between your device and your Wi-Fi network. OpenWRT will be able to capture your traffic. After, you’ll be able to analyze this traffic using Wireshark and see what data, if any, your VPN is leaking.
Note: You will also need an empty USB stick or SD card for this method.
1. Install Wireshark on your PC or Mac
The first step is to install Wireshark on your computer. Here’s how to do it:
- Go to Wireshark’s download page.
- Download the Windows Installer (64-bit) or the macOS package.
- Click on “Next” and confirm you’ve read the user agreement by clicking on “Noted.”
- Choose the Wireshark components you want to install. We recommend installing all of them.
- Click through all of the menus until you see the “Install” button. Click on it and wait for the installation to complete.
- You’ll see a few extra installation options, as shown below. You can leave them be, and just click on Install.
2. Install OpenWRT on Raspberry Pi
Now that you have Wireshark installed, we’ll look at how to install OpenWRT on your Raspberry Pi.
- Select and download the right OpenWRT install image for your Raspberry Pi version.
- Download the Raspberry Pi imager. This is the program that allows you to get OpenWRT on your USB stick or SD card.
- Select “Choose OS,” as indicated above.
- Scroll down and click on “Use Custom.”
- Navigate to the OpenWRT install image you downloaded and select it.
- Under “Choose Storage,” just select your SD card or the USB drive. The Raspberry Pi imager will completely wipe the chosen storage device before transferring OpenWRT to it.
- Click on “Write.” This will transfer OpenWRT to your storage device.
3. Set up OpenWRT
You’re now all ready to start up your Raspberry Pi and use OpenWRT. You’ll just need to set it up. Here’s how to do so:
- Connect your Raspberry Pi to your PC using an ethernet cable.
- Enter the following IP address in your browser: 192.168.1.1.
- When you get to the login screen, change your login information.
4. Using OpenWRT to capture your mobile traffic
Now, it’s time to capture your mobile traffic using OpenWRT. Follow these steps:
- Go to the LAN interface of your Raspberry Pi (Interfaces > Lan).
- Next to “Protocol,” select “Static address.”
- Set the local IP address (IPv4 address) to the same network as your router.
- Click on “Save.”
- Open “Bridge device: br-lan.”
- Set “Bridge ports” to “eth0.” This acts as a virtual WiFi (wireless) to ethernet (wired) converter. It allows you to connect your Raspberry Pi to your WiFi network and act as a bridge between your smartphone and your outgoing data traffic.
- Click on “Save.”
- Install tcpdump on the router.
- Connect the mobile device to the OpenWRT router and disable cellular data.
- Connect your VPN on your mobile.
- Follow OpenWRT’s instructions for capturing packets with tcpdump on the router’s “br-lan” device.
- WireShark will launch automatically and start displaying traffic.
- Clean up the traffic using this display filter, substituting the mobile device’s IP address “(ip.src== || ip.dst==) and (tls || http || dns || tcp || udp) and !wg and !openvpn and !icmp and !mdns.”
- Any packets visible in WireShark indicate a probable mobile VPN leak.
How to Fix Mobile VPN Leaks
In this section, we’ll focus on how to fix a VPN leak on mobile, in case you spotted any using the method above. We’ll discuss two methods you can try out to fix your VPN leak.
Fix Android VPN leaks using Android debug bridge (adb)
Android debug bridge (adb) is a program that allows you to make certain (advanced) modifications to your Android device.
One of these modifications is altering or disabling connectivity checks from different apps. This is generally what causes mobile VPN leaks.
First, you will need to configure your phone to grant adb access to it. Follow the steps below to do so.
Configuring adb on Android
- Go to “Settings.”
- Tap “About Phone.”
- Enable “Developer Mode” by tapping your phone’s build number seven times. Depending on your device, you might have to tap your mobile OS instead, like in the screenshot below.
- Go back to general settings (or on some devices, go to “Additional Settings”) and navigate to “Developer Options” or something similar. Tap this option.
- Enable “USB Debugging.”
You’ve now gone through the most important part of the adb phone setup. Now it’s time to set up adb on your PC. Follow the steps below to do so.
Set up adb on Windows
- Go to this page and download the right Android SDK Platform Tools package for Windows.
- Extract the contents of the zip file to a location of your choice (one you will remember).
- Open Windows Explorer and navigate to the folder where you saved the platform tools.
- Hold shift and click on your right mouse button. Now, select “Open command window here.”
- Connect your smartphone to your PC using a USB cable. When prompted, choose “File transfer (MTP mode).”
- Enter the following command into the Command Prompt window: “adb devices.”
- You will see a prompt on your phone asking whether you want to accept or deny debugging access. Tap “OK.”
- Enter “adb devices” once again in the command window.
Set up adb on macOS
- Go to this page and download the right Android SDK Platform Tools package for macOS.
- Extract the contents of the zip file to a location of your choice (one you will remember).
- Open “Terminal.”
- Enter the exact path name of where you saved your Android SDK Platform Tools, for instance: /Users/bd/Documents/adb/.
- Connect your Android phone to your Mac using a compatible USB cable. When prompted, choose “file transfer (MTP mode.”
- Put the following command into the Terminal: “./adb devices“
- Check your phone screen for a message and confirm that you want to “Allow USB debugging.”
Now that you’ve installed adb on your PC, you’re all set to start using it to fix mobile VPN leaks.
Disable connectivity checks on Android using adb
Whether or not Android performs connectivity checks, is governed by the captive portal mode setting. A captive portal is essentially the screen you get to see when you connect to a guest network, like Wi-Fi at Starbucks.
It’s important to keep your phone connected to your PC during this process. You can set the captive portal mode to one of three values:
- 0: This will make sure your system doesn’t attempt to detect captive portals. As a result, connectivity checks will be disabled.
- 1: This is the default setting. It simply directs you to a sign-in page when a captive portal is detected.
- 2: When a captive portal is detected, this setting will interrupt your network connection. Furthermore, your device will no longer reconnect to this network in the future.
To disable connectivity checks, and, as such, most Android VPN leaks, you have to choose the first option (“0”).
Fix mobile VPN leaks using a VPN router
Using a VPN router is a great way to fix mobile VPN leaks, especially if you’re connected to your home network.
By putting your router in charge of securing your network connection, any internal flaws in your mobile OS can no longer cause data leaks. That’s what makes VPN routers so useful in combatting VPN leaks.
Of course, this method will only work as long as you’re able to gain admin access to your VPN router. Therefore, it’s not a useful solution for people who are on the move a lot and often connect to public WiFi networks.
Generally, some routers are inherently safer than others. You can browse through our list of the very best VPN routers to find the best one for your needs.
NordVPN: The Best VPN to Prevent Mobile VPN Leaks on Android
Unfortunately, no VPN provider can address the inherent Android OS flaws that cause VPN leaks. However, a trustworthy VPN provider can significantly improve the overall privacy and security within the Android framework. In our opinion, few VPN providers do this as well as NordVPN.
NordVPN has a dedicated VPN app for both Android and iOS. It also offers a range of features with a focus on privacy and security, including:
- AES 256-bit encryption
- Top VPN protocols (NordLynx, IKEv2/IPsec, and OpenVPN)
- Obfuscated servers
- DNS and WebRTC leak protection
DNS leak protection will greatly reduce the chance of your ISP and other parties seeing what websites you visit. WebRTC leak protection aims to prevent your real IP address from being exposed this way.
NordVPN offers the possibility to connect up to six devices concurrently. NordVPN doesn’t just protect you from mobile leaks, but it also helps you unblock
Lastly, for those wanting some entertainment use out of their VPN, NordVPN is able to unblock many streaming services. Among these are Netflix, Hulu, HBO Max, and many others. It also offers a 30-day money-back guarantee.
- Fast and large worldwide network of VPN servers
- Perfect for privacy and streaming
- Trusted by many, with over 14 million users
You can also use the NordVPN free trial which unlocks all features of the VPN, so you can really experience the benefits it offers.
Surfshark: The Best VPN to Prevent Mobile VPN Leaks on iOS
There are several great VPNs for iOS that greatly limit the chance of “non-iOS-induced” VPN leaks. At the top of this list is Surfshark, which also has dedicated apps for iOS and Android.
Surfshark offers an array of different privacy-focused features, including:
- Kill switch and split tunneling
- WireGuard, OpenVPN, IKEv2 protocol support
- DNS and WebRTC leak protection
- AES 256-bit encryption
Surfshark also offers some advanced VPN leak detection capabilities. It offers tests for both DNS leaks and WebRTC leaks. This is a useful feature to prevent any major VPN leaks and regularly test your device.
Another great advantage of Surfshark is that it allows for an unlimited number of simultaneous connections. As such, you can use one account with as many devices as you want.
Lastly, Surfshark is one of the most affordable premium VPN providers out there. There’s also a 30-day money-back guarantee.
- Very user-friendly and works with Netflix and torrents
- 30-day money-back guarantee. No questions asked!
- Cheap with many extra options
You can also go for a Surfshark free trial to check out the VPN for up to 30 days!
The Bottom Line
As we discussed in this article, mobile VPN leaks can be hard to prevent. In fact, often they’re caused by inherent flaws in your mobile operating system. Fortunately, we presented you with a test for VPN leaks on mobile and a few ways to fix them.
Do you want to learn more about other VPN vulnerabilities and weaknesses and how to solve or mitigate these? Then be sure to also check out the articles below:
- How to Do a VPN Test for Speed and Security
- My VPN Doesn’t Work: How to Fix the Most Common VPN Issues
- Disadvantages of a VPN
Do you have a specific question about mobile VPN leaks and how to spot and fix them? Check out our FAQ below to see if we’ve already answered your question. If we haven’t, leave a comment below and we’ll get back to you as soon as possible!
A mobile VPN leak occurs when data that your VPN should typically protect or hide becomes visible or available to others. The data in question can be anything from your DNS requests (DNS leak) to your IP address (WebRTC leak) or your actual data traffic if the latter isn’t adequately encrypted.
This strongly depends on the type of VPN leak. For instance, if your IP address is leaked, online parties could identify much easier who you are, so this harms your privacy.
On the other hand, if your VPN is bypassed altogether and doesn’t encrypt your data, someone could actually obtain your sensitive personal data.
When it comes to desktop VPN leaks, there are plenty of online tools to detect them. You can find these with a quick and easy search. On mobile, it’s a bit more complicated. You can use a Raspberry Pi to detect mobile VPN leaks.
The fix you should choose depends a lot on your device and the cause of the VPN leak. On Android, for instance, it often helps to turn off connectivity checks, while on iOS enabling airplane mode might do the trick. Another great method that works for lots of devices, is to use a VPN router.
