4 ms·

This is not the first time "serious" flaws have been found with DPAPI. Here's another example: https://cqureacademy.com/blog/windows-internals/black-hat-europe-

This is not the first time "serious" flaws have been found with DPAPI. Here's another example: https://cqureacademy.com/blog/windows-internals/black-hat-europe-2017 https://cqureacademy.com/blog/windows-internals/black-hat-eu... In this case, it turns out that if you have access to the domain controller as admin, you can decrypt DPAPI secrets by using user's private keys stored there (keys for DPAPI need to "roam" with the account, as do keys for EFS, so it's not surprising that they're there). Likewise, it also turns out that if you decline to provide a password (encryption key) for secrets stored in a PKCS#12 blob (PFX), Windows makes one up for you and this is deterministically bound to your user account (and can be broken with said access). Neither of these "attacks" cross a privilege boundary - it just turns out crypto isn't magic. As pointed out by other commenters, bitlocker should be enough for most people, but the truth is that if you don't trust your physical environment you need to put in place physical access controls, tamper detection, have a TPM etc, as well as full disk encryption.

lordlimecat 7y ago
A domain admin can access the user's long term kerberos encryption keys and generate arbitrary key tabs for that user. If you have domain admin, you can access EVERYTHING in that forest and any two way trusted forest.
- zahllos 7y ago
  Of course. Hence it isn't really a flaw if you need domain admin to gain access. It's a vulnerability or major fault if an ordinary user can get access, or worse an unauthenticated user / someone with a specially crafted network packet. Obviously domain admin accounts need to be suitably protected and you hint at this in your comment (ESAE) but that's another matter. This bug is another such example - you have to decide to enable this and ask Windows to store your password to log you in, and that's exactly what happens, including exposure of any secrets protected via DPAPI / bound to your account. It's a convenience feature, working as intended. Perhaps the impact should be made clearer, but there are even legitimate reasons for this sort of functionality, such as self-service kiosks that are often built with windows images.

lordlimecat 7y ago

A domain admin can access the user's long term kerberos encryption keys and generate arbitrary key tabs for that user. If you have domain admin, you can access EVERYTHING in that forest and any two way trusted forest.

zahllos 7y ago
Of course. Hence it isn't really a flaw if you need domain admin to gain access. It's a vulnerability or major fault if an ordinary user can get access, or worse an unauthenticated user / someone with a specially crafted network packet. Obviously domain admin accounts need to be suitably protected and you hint at this in your comment (ESAE) but that's another matter. This bug is another such example - you have to decide to enable this and ask Windows to store your password to log you in, and that's exactly what happens, including exposure of any secrets protected via DPAPI / bound to your account. It's a convenience feature, working as intended. Perhaps the impact should be made clearer, but there are even legitimate reasons for this sort of functionality, such as self-service kiosks that are often built with windows images.