Custom Cert on > Android 7 inkl. burp config

# Keep it clean
> mkdir certificates && cd certificates

# Borrow the default openssl.cnf (location may differ, see note)
> cp /etc/pki/tls/openssl.cnf ./


# Create a private key. 
# It's important to have the v3_ca extension and to supply the openssl.cnf file
> openssl req -x509 -days 730 -nodes -newkey rsa:2048 -outform der -keyout server.key -out ca.der -extensions v3_ca -config openssl.cnf
Generating a 2048 bit RSA private key
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writing new private key to 'server.key'
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You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:BE
State or Province Name (full name) [Some-State]:NVISO CA
Locality Name (eg, city) []:NVISO CA
Organization Name (eg, company) [Internet Widgits Pty Ltd]:NVISO CA
Organizational Unit Name (eg, section) []:NVISO CA
Common Name (e.g. server FQDN or YOUR name) []:NVISO CA
Email Address []:NVISO CA

# Convert to der format
> openssl rsa -in server.key -inform pem -out server.key.der -outform der
writing RSA key

# Convert key to pkcs8 format
> openssl pkcs8 -topk8 -in server.key.der -inform der -out server.key.pkcs8.der -outform der -nocrypt

Convert the public key
openssl x509 -inform der -in ca.der -out ca.pem
openssl x509 -inform PEM -subject_hash_old -in ca.pem | head -1
cp ca.pem a58355c2.0
openssl x509 -inform PEM -text -in ca.pem -out /dev/null>> a58355c2.0
Copy the cert to the phone
adb push a58355c2.0 /data/local/tmp
adb shell
In the adb shell

su
mount -o rw,remount /system
mv /data/local/tmp/a58355c2.0 /system/etc/security/cacerts/
chown root:root /system/etc/security/cacerts/a58355c2.0
chmod 644 /system/etc/security/cacerts/a58355c2.0
reboot

#Import the cert into BurpSuite
Go to the proxy settings page and choose “Import / Export CA Certificate” -> “Import” -> “Certificate and priate key in DER format”

https://blog.nviso.be/2018/01/31/using-a-custom-root-ca-with-burp-for-inspecting-android-n-traffic/
https://awakened1712.github.io/hacking/hacking-install-ca-android/