Howto Extract 2FA Tokens from FreeOTP

extract_freeotp_tokens.md

Extracting 2FA tokens from FreeOTP

Backing up FreeOTP

Using adb, create a backup of the app using the following command:

adb backup -f freeotp-backup.ab -apk org.fedorahosted.freeotp

org.fedorahosted.freeotp is the app ID for FreeOTP.

This will ask, on the phone, for a password to encrypt the backup. Proceed with a password.

Manually extracting the backup

The backups are some form of encrypted tar file. Android Backup Extractor can decrypt them. It's available on the AUR as android-backup-extractor-git.

Use it like so (this command will ask you for the password you just set to decrypt it):

abe unpack freeotp-backup.ab freeotp-backup.tar
# Or
java -jar abe-all.jar unpack freeotp-backup.ab freeotp-backup.tar

Then extract the generated tar file:

$ tar xvf freeotp-backup.tar
apps/org.fedorahosted.freeotp/_manifest
apps/org.fedorahosted.freeotp/sp/tokens.xml

We don't care about the manifest file, so let's look at apps/org.fedorahosted.freeotp/sp/tokens.xml.

Extracting Tokens

To understand what's going on read this.

To quickly extract your tokens, save this python code in a file named extract_freeotp_tokens.py.

import xml.etree.ElementTree as ET
import json
import base64


token_files = "./apps/org.fedorahosted.freeotp/sp/tokens.xml"

with open(token_files, "r") as f:
    tree = ET.parse(f).getroot()
    tokens = tree.findall('string')

    for token in tokens:
        if token.get('name') == "tokenOrder":
            continue

        jtoken = json.loads(token.text)
        secret_byte = bytes((x % 256) for x in jtoken["secret"])
        secret_key = base64.b32encode(secret_byte).decode()
        print(f"{token.get('name')}: {secret_key}")

and run it:

python ./extract_freeotp_tokens.py

Now you can import your 2FA tokens in other tools such as KeepassXC.