I have received advice from way to many people to not use your password manager as a 2nd factor be ause 1) It's actually become the only point if failure (your pw getting hacked). 2) Both factors protected and saved on the same spot
1Password in particular encrypts your vault with your master password and importantly an additional 128 bit secret key that is meant to be kept somewhere physically (e.g. in your safe). This key is needed the first time your vault is decrypted (e.g. a new device)
An attacker would need to have access to all of the following:
a) your encrypted vault
b) your master password
c) an 128-bit secret key
in order for the fears you've outlaid to be realised.
Really the only attack vector I can see is a physically compromised device (brute forcing is out of the question). In which case, they'd still need to somehow know your Master password and you're no more vulnerable considering your OTP is likely to be in an application on your phone anyway.
Since your own computer will typically have the vault unlocked, you don't need a+b+c. You can suffice with a circa 2000s Sony Music cd. Or any driveby malware, or malvertisement, etc.
Using the 2nd factor on another device as the first means attackers need to either compromise 2 devices, or compromise a single point higher up in the hierarchy (e.g., your google account).
If there’s malware on your PC that has complete access to your system memory you are screwed in every single way possible. I’m perfectly comfortable with having my OTP coupled with my passwords given this is the only real attack vector and requires an actively unlocked vault to expose secrets.
If this is the case, what’s stopping the malware from adding a key logger and MITMing your input to your bank’s website, Gmail or Coinbase?
