Help! All data in mybook live gone and owner password unknown

WD Legacy Products My Book Live
415

I know it is already too late, but maybe some of you still have an unaffected MyBook.

I would like to share with you how to fix the security vulnerability CVE-2018-18472:

Access SSH and edit file (e.g. with “nano”)
/var/www/Admin/webapp/includes/languageConfiguration.php

First change
Search for:

exec("sudo bash -c '(echo \"language {$changes["language"]}\">/etc/language.conf)'", $output, $retVal);

Replace with:

if (!preg_match('/^[a-z]{2}_[A-Z]{2}$/', $changes["language"], $dummy)) return 'BAD_REQUEST';
exec("sudo bash -c '(echo '\"'\"".escapeshellarg("language {$changes["language"]}")."\"'\"'>/etc/language.conf)'", $output, $retVal);

Second change:
Search for:

exec("sudo bash -c '(echo \"language {$lang["language"]}\">/etc/language.conf)'", $output, $retVal);

Replace with:

if (!preg_match('/^[a-z]{2}_[A-Z]{2}$/', $lang["language"], $dummy)) return 'BAD_REQUEST';
exec("sudo bash -c '(echo '\"'\"".escapeshellarg("language {$lang["language"]}")."\"'\"'>/etc/language.conf)'", $output, $retVal);

See, this is all you need to do. WD knew about this bug in 2018 and they refused to change these TWO LINES of code, just because the product is “EndOfLife”…

Of course, there might be other bugs, but this is the biggest of all. I am not aware of other code injection bugs, but I will now review the code and see if there is more. I really would like to keep my MyBook because I hate throwing working hardware away…

EDIT: My first version contained an error. This is the correct one!!!
Note: The preg_match line is not required to fix the vulnerability, but it avoids that hackers write garbage in your /etc/language.conf file.

EDIT 2: My code review is done. I did not find further root command injections which don’t require authentication

EDIT 3: Additional security settings you should consider

  1. Disable “remote access” in the UI
  2. Change “connection options” from “automatic” to “manual”, this disables UPnP
    (thanks to @WDMyBookDead for that hint! They posted a screenshot)
  3. Disable UPnP in your router
  4. Disable factory reset:
    If you believe that you will never need the factory restore, I recommend disabling it completely.
    Edit /usr/local/sbin/factoryRestore.sh and wipeFactoryRestore.sh and change line #2 to exit.
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