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Introduction:
Android 14 represents a significant leap in mobile security by hardening the operating system’s certificate store, making traditional methods for adding a trusted CA certificate—like those from Burp Suite for interception—obsolete. This change, designed to protect users from sophisticated malware, directly challenges security professionals and ethical hackers who rely on traffic analysis for mobile app assessments. This guide explores proven technical workarounds to bypass SSL pinning and install a custom CA, ensuring your penetration testing toolkit remains effective against the latest Android defenses.
Learning Objectives:
- Understand the architectural changes in Android 14’s certificate storage (APEX) that break traditional CA installation methods.
- Master multiple procedural techniques, from ADB commands to system-level modifications, to successfully deploy the Burp Suite CA certificate.
- Learn complementary methods for bypassing SSL certificate pinning within applications when system-level trust is insufficient.
You Should Know:
- The Root of the Problem: Android 14’s APEX and Read-Only Filesystems
Android 14 has moved critical system components, including the conscrypt TLS library, into APEX modules (Android PEXtensions). These are mounted from read-only partitions. The trusted system CA certificates now reside at `/apex/com.android.conscrypt/cacerts` instead of the legacy/system/etc/security/cacerts. Direct writes to this location are impossible on a non-rooted device, breaking the simple ADB push method used in earlier versions.
Step‑by‑step guide explaining what this does and how to use it.
First, you must extract the Burp Suite CA certificate.
1. On your Burp Suite proxy machine, navigate to http://burpsuite` (or your proxy IP) from a browser.cacert.der
2. Click "CA Certificate" to download the DER file.openssl x509 -inform DER -in cacert.der -out cacert.pem
3. Convert it to the PEM format with a subject hash link, which Android requires:. Then, generate the hash:openssl x509 -inform PEM -subject_hash_old -in cacert.pem | head -1. This outputs a string like9a5ba575. Rename the PEM file:mv cacert.pem 9a5ba575.0.remount failed`. This confirms the read-only barrier.
4. Attempting to push this to the new path will fail: `adb root && adb remount` will likely return
- Method 1: The ADB Override for User-Debug Builds and Emulators
If you are testing on an Android emulator or a physical device with a user-debug build (common in developer builds), you can use the manual certificate installation feature intended for user CAs in a different location. This method does not achieve true system-level trust but works for many apps.
Step‑by‑step guide explaining what this does and how to use it.
1. Prepare your certificate in the proper format. Use the `cacert.pem` from the previous step.
2. Push the certificate to the device’s user storage: adb push cacert.pem /sdcard/Download/.
3. On the Android device, go to Settings > Security & Privacy > More security settings > Encryption & credentials > Install a certificate > CA certificate.
4. A warning will appear; proceed and navigate to `/storage/emulated/0/Download/` to select the `cacert.pem` file.
5. Name the certificate (e.g., “PortSwigger Burp”) and install it. This installs the certificate to the user credential store (/data/misc/user/0/cacerts-added/). Important: You must set a device PIN/password if you haven’t already, as this is a security requirement.
6. While useful, note that apps targeting Android API level 24+ can choose to not trust user-added CAs, limiting this method’s effectiveness.
- Method 2: System-Level Installation via Magisk (Root Required)
For a persistent, system-level installation that is trusted by all applications, root access via Magisk is currently the most reliable method. This involves creating a Magisk module that places your CA certificate into the correct system store at boot.
Step‑by‑step guide explaining what this does and how to use it.
1. Ensure your device is rooted with Magisk installed.
2. Create a module structure on your computer:
BurpCA/ ├── post-fs-data.sh ├── system/ │ └── apex/ │ └── com.android.conscrypt/ │ └── cacerts/ │ └── 9a5ba575.0 └── module.prop
3. The `post-fs-data.sh` script must copy the certificate:
!/system/bin/sh
MODDIR=${0%/}
cp -f $MODDIR/system/apex/com.android.conscrypt/cacerts/ /apex/com.android.conscrypt/cacerts/
chmod 644 /apex/com.android.conscrypt/cacerts/
Make it executable: `chmod +x post-fs-data.sh`.
4. Create a simple `module.prop` file:
id=burpca name=Burp CA Installer version=v1.0 author=YourName description=Installs Burp CA to system store on Android 14+.
5. Zip the contents (not the top folder): `cd BurpCA && zip -r ../BurpCA.zip .`
6. Install the zip file via the Magisk app, reboot, and verify your Burp certificate is now present and trusted system-wide.
- Method 3: Dynamic Bypass with Frida for SSL Pinning
Even with a system-trusted CA, many apps implement SSL pinning, which checks for a specific certificate. When you encounter such an app, you need a runtime hooking tool like Frida to bypass the pinning logic.
Step‑by‑step guide explaining what this does and how to use it.
1. Install Frida server on your rooted Android device. Download the correct ARM version and push it: adb push frida-server /data/local/tmp/. Then, execute it: adb shell "chmod 755 /data/local/tmp/frida-server && /data/local/tmp/frida-server &".
2. On your host machine, install the Frida client: pip install frida-tools.
3. Use a Frida script to bypass common pinning libraries. Save the following as pinning_bypass.js:
// Bypass for OkHttp3 CertificatePinner
Java.perform(function() {
var CertificatePinner = Java.use("okhttp3.CertificatePinner");
CertificatePinner.check.overload('java.lang.String', '[Ljava.security.cert.Certificate;').implementation = function() {
console.log("[+] Bypassing OkHttp3 CertificatePinner");
};
});
// Bypass for TrustManager
Java.perform(function() {
var X509TrustManager = Java.use('javax.net.ssl.X509TrustManager');
var TrustManager = Java.registerClass({
name: 'com.example.TrustManager',
implements: [bash],
methods: {
checkClientTrusted: function() {},
checkServerTrusted: function() {},
getAcceptedIssuers: function() { return []; }
}
});
var SSLContext = Java.use('javax.net.ssl.SSLContext');
var context = SSLContext.getInstance("TLS");
context.init(null, [TrustManager.$new()], null);
context.getSocketFactory().createSocket.overload('java.lang.String', 'int').implementation = function(host, port) {
console.log("[+] Custom TrustManager used for: " + host);
return this.createSocket(host, port);
};
});
4. Attach to the target app: frida -U -l pinning_bypass.js -f com.target.app --no-pause. This script hooks into key security functions and neutralizes the pinning checks.
5. Hardening Your Proxy Setup: Avoiding Detection
Modern mobile applications, especially in banking and fintech, employ advanced certificate transparency and binding checks. Simply having a trusted CA may not be enough; you must configure Burp Suite to be as stealthy as possible.
Step‑by‑step guide explaining what this does and how to use it.
1. Invisible Proxying: In Burp Suite Project options, go to Connections and enable Support invisible proxying. This helps handle non-proxy-aware clients.
2. Match Server TLS Fingerprints: Some apps validate the proxy’s TLS stack. Use the `jarm.py` tool to fingerprint the target server’s TLS configuration (JARM fingerprint). In Burp’s TLS settings, try to mimic the server’s TLS version, cipher suites, and extensions order.
3. Response Modification: Use Burp’s Match and Replace rules (Proxy > Options) to strip any security headers that might reveal interception, such as `Public-Key-Pins` or Expect-CT.
What Undercode Say:
- The Cat-and-Mouse Game Escalates: Google’s shift to APEX modules is a clear win for default security but also raises the barrier to entry for legitimate security research, potentially centralizing testing capabilities to only those with deep system expertise or specific device builds.
- Root Remains King for Depth: While user-certificate installs and runtime hooking provide avenues for testing, achieving true system-level persistence for tools like Burp Suite currently necessitates root access, reinforcing the critical role of Magisk and similar tools in the professional pentester’s mobile arsenal.
Prediction:
The trajectory set by Android 14 indicates a future where system integrity protections will become even more granular, potentially leveraging hardware-backed security modules (like Titan M2) to validate the entire boot chain and system state, including the certificate store. This will make temporary software-based root solutions increasingly difficult. The response from the security community will likely bifurcate: one path focusing on developing more sophisticated emulation and virtualization-based testing platforms that can control the environment at a hypervisor level, and another pursuing official, sandboxed “developer mode” APIs from Google that allow authorized, auditable security testing without compromising the core security model for everyday users. The tools themselves, like Frida and Magisk, will evolve to operate within these new constrained environments, possibly leveraging undiscovered exploits or official partnerships.
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IT/Security Reporter URL:
Reported By: Bhanuprakash Goud – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
