How to get charles proxy work with Android 7 nougat?

Question

Android 7 introduced some changes to the way certificates are handled (http://android-developers.blogspot.com/2016/07/changes-to-trusted-certificate.html) and somehow I cannot make my Charles proxy work any more.

My network_security_config.xml:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config>
        <trust-anchors>
            <certificates src="system" />
        </trust-anchors>
    </base-config>
    <debug-overrides>
        <trust-anchors>
            <certificates src="user" />
        </trust-anchors>
    </debug-overrides>
</network-security-config>

I'm running in debug mode. But no matter what, I get javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found..

Needless to say, I did install a pfx certificate from Settings -> Security -> Install from storage. The certificate shows in User Credentials but not in Trusted credentials -> User. On my lollipop device, the certificates are listed there.

I'm using okhttp3 as HTTP library.

Any idea what I am doing wrong ?

Answer 1

The solution is do not use .p12, just navigate with Chrome (with configured proxy on wifi) to http://charlesproxy.com/getssl and install downloaded .pem file.

I had exactly the same problem on my Nexus 5X running Android 7.0. There was previously exported .p12 from Charles 3.11.5 (Help->SSL Proxying->Export Charles Root certificate and Private key). When I tried to install .p12 from phone (Settings->Security->Install from storage) it appears only under "User credentials" and never at "Trusted credentials", and of course SSL with Charles proxy did not work.

The total "how-to" for Android 7.0 would be like that:

1. Configure WiFi + proxy (how Charles requires it). Connect it.
2. On device, navigate with Chrome to http://charlesproxy.com/getssl, accept request for download .pem, then press "open", it launches "Certificate installer" app. Use it to install the certificate as "VPN and apps".
3. Put the attribute android:networkSecurityConfig="@xml/network_security_config" to <application> at Manifest.xml
4. Create res/xml/network_security_config.xml with content from the first post (it is totally correct).
5. Launch Charles and app and have fun.

P.S. Check date/time on the device. It should be correct.