What risks may exist, living with TLS decrypting proxy?

edited July 2019 in Lounge

My company introduced ZScaler Web Security as a corporate internet proxy, that is capable to decrypt all TLS communication through the proxy, using MITM-like method with wild-card server certificate issued by ZScaler CA. My company forces employees to install ZScaler CA certificate manually for all client PCs.

Of course I trust my company and ZScaler never leak or badly exploit my sensitive information, but I think I need to know what kind of potential risks would exist when I use ZScaler + 1Password, that intentionally breaks E2E TLS security concept.

In this sense, I would like to precisely know, what kind of information could be potentially peeked by my company or ZScaler:
- Is the my master password conveyed in clear text over TLS tunnel?
- Are my meta information entries (e.g. site names, login IDs, secure notes, etc..) conveyed in clear text over TLS tunnel?
- Are my passwords conveyed in clear text over TLS tunnel?

I suppose my.1password.com access or API access by 1Password apps may have different conditions, appreciate if I can see such differences.

Thank you very much for your advise in advance,

1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
Sync Type: Not Provided


  • brentybrenty

    Team Member

    @shingo: It's a good question, with an interesting answer. In short, a person-in-the-middle capable of decrypting all of your TLS communications breaks the fundamental security of the internet. generally speaking, that puts you in the uncomfortable position of not being able to trust that you're communicating with who you think you are, and that everything you do over the internet which relies on TLS for end-to-end privacy and security is in question.

    Fortunately, 1Password doesn't rely on TLS alone for its security. We're really strict about that, because if TLS is broken, you're gonna have problems. But your 1Password data being exposed in transit isn't one of them:

    Three layers of encryption keeps you safe when SSL/TLS fails

    1Password data is always encrypted and decrypted locally, so at the lowest "layer", your data is protected even if someone steals your device. On top of that, we use Secure Remote Password protocol to avoid you ever needing to transmit your credentials, and in order for us to avoid having them, which would be a huge liability for us and our customers:

    Developers: How we use SRP, and you can too

    On top of all of that should also be TLS, which the modern internet is built on. But the unfortunate reality is that many institutions nowadays, both public and private, don't respect individual privacy, so we don't rely on that alone.

    So, to answer your specific questions directly,

    Is the my master password conveyed in clear text over TLS tunnel?

    No, not by 1Password, never. However, I will say that you should be careful where you enter it. Someone with the ability to insert themselves in all of your communications -- whether that be an employer or an attacker -- could play all kinds of games, and either maliciously or through negligence capture what you enter into websites and do pretty much anything with it. So take care to only enter your Master Password into an app (including and especially the one that runs in your browser) after verifying that it is from 1Password, not something someone else has foisted on you.

    Are my meta information entries (e.g. site names, login IDs, secure notes, etc..) conveyed in clear text over TLS tunnel?

    No, not by 1Password as part of your data in it, as all of that is encrypted. But any time you request any URL over the network, it would be visible to those inserting themselves into your internet communications.

    Are my passwords conveyed in clear text over TLS tunnel?

    No, not by 1Password. But in the vast majority of cases, when you enter a password to sign into a website, it is protected only by TLS. So when TLS is compromised, the password is effectively "in the clear" for the person-in-the-middle. Again, not an issue for things inside 1Password, but you should be aware that once it is used outside of 1Password, 1Password can't protect it. While you may personally trust your company and/or others involved, customers also trusted major antivirus vendors computer manufacturers who ended up logging and exposing customer information in a similar fashion. Even accidentally, the consequences are the same.

    Kind of depressing, but knowledge is power. I hope this helps. Please let me know if you have any other questions.

  • Thank you @brenty, for your quick and valuable response. I'm very impressed that 1Password team can give me such detailed answer so quickly, and realized your culture to prioritize security aspects :)

    Now I understand that regardless of the my.1password.com website or App-API, all transactions over the internet are additionally encrypted on the top of TLS layer. Therefore I don't need to worry about my company or ZScaler can peek actual contents of my 1Password vault as well as master password. I felt really relaxed in this regard.

    For more generic "the internet security best-practice" aspects you kindly mentioned, I totally agree all with you. I hope it helps someone who sees our conversation afterwards :chuffed: Be aware of phishing as well as all subsequent internet access, including site specific password, will be potentially under the supervision of your IT.

    Thanks Again,

  • brentybrenty

    Team Member

    @shingo: You're very welcome! And thanks for bearing with my long-winded answer. Indeed, since others will likely view this discussion I want to be sure I don't gloss things over and cause confusion, as it's a complex issue. It's simpler, in a sense, in the context of 1Password; but I wouldn't want to give anyone the impression that 1Password can protect against other, external factors inherent in that kind of a scenario, which nevertheless have an impact on our overall security. Cheers!

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