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KeePass – questionable security
21–30 of 231 posts
Re: KeePass – questionable security
#22what is the problem with the singleton?
Any takers on that question?
I assume that they are implying that the code is not constant time. In this snippet, the code bails as soon as a deviation is detected. This can, in theory, allow an attacker to determine the desired value by measuring the time taken to reject incorrect options. I haven't reviewed the code to see if this is actually a problem, but that's my guess for why it was highlighted.
Re: KeePass – questionable security
#23Earlier quoted context omitted.
There are 2 problems here. (1) The c# .NET implementation is lacking; (2) the fundamental crypto design of the kdbx database (which is shared by all implementations, in any language) is lacking.
Yes, but since this isn't some networked service I'm not as concerned about the general quality of the code. Offline attacks really have to focus on the encrypted password database. If an attacker has local access you're already owned -- they could just modify the application to do whatever they want... or keylog you, etc. The safety of your database in a world where your keepass database is leaked due to a Dropbox a…
It's not 100% offline. As you said, if they manage to access your Dropbox, they could theoretically sync an altered database back to you. If the application leaks some information while attempting to open the database or can be made to leak information, that would be bad.
Re: KeePass – questionable security
#24What about KeePassX? That's what I've been using for a long time now. It's not written in C#, but C++ EDIT: source: https://github.com/keepassx/keepassx
KeePassX uses an older database format (KDB) than KeePass 2.x (KDBX4). It also lacks AEAD and is actually less secure than KDBX4 according to the analyses I've read.
Re: KeePass – questionable security
#25Ok, your password database was affected by malicious modification. So what? How it can break the confidentiality of your data? Update: By the way, what's wrong with the bytearray compare code snippet?
The array comparison? It's literally the textbook example of a timing sidechannel. Though I won't speculate if it's a real problem here, since I have no idea what data is being compared.
Do you care about that kind of side channel for an offline vault?
If your adversaries are on your box while you operate your vault, then you have already lost because they will also have keyloggers, strace, etc.
Re: KeePass – questionable security
#26And I thought I was safe using Keepass on Dropbox.
Any recommendations for password managing?
Re: KeePass – questionable security
#27Ok, your password database was affected by malicious modification. So what? How it can break the confidentiality of your data? Update: By the way, what's wrong with the bytearray compare code snippet?
I notice that the "change-password" function of yourbank.com is accidentally being served over HTTP instead of HTTPS. I just need to trick you into changing your password. I have access to your kdbx db (ex. you sync to Dropbox and I'm Dropbox employee). I can alter the kdbx file to change your password so that it is no longer valid. KeePass doesn't complain at all. You have a WTF moment and try to change your passwor…
Wait, you just inserted an invalid password in my database, how do I change my password? Hell, the only way I'll even realize something's wrong is by trying to log in in the first place, and, if you can see my connection, why would you have me enter a wrong password, rather than the right one?
Re: KeePass – questionable security
#28I have been a KeePass user for many years and I always used this in conjunction with a TrueCrypt container meaning that I keep my kdbx file inside the container. Yes TrueCrypt isn't "safe" but at this point it will take one highly motivated attacker to steal my "important" passwords. Sadly I am not aware of any audits related to KeePass but I would be happy to read one!
Why do you say TrueCrypt isn't safe? I only skimmed the audit, but it seemed to have an overall positive impression, no?
Well I believe it is safe for my personal purpose but if you read the note the author left on Truecrypt website/software you can clearly read :
WARNING: Using TrueCrypt is not secure as it may contain unfixed security issues
If I recall the audit was positive but who knows why this message was plastered everywhere when "they" decided to call it quits.
Re: KeePass – questionable security
#29Answering on whether somebody did an audit for KeePass
http://keepass.info/ratings.html
I'm not sure but one may look at
https://www.allianz-fuer-cybersicherheit.de/ACS/DE/_download...
and
http://www.ssi.gouv.fr/entreprise/certification_cspn/keepass...
Re: KeePass – questionable security
#30Ok, your password database was affected by malicious modification. So what? How it can break the confidentiality of your data? Update: By the way, what's wrong with the bytearray compare code snippet?
The array comparison? It's literally the textbook example of a timing sidechannel. Though I won't speculate if it's a real problem here, since I have no idea what data is being compared.
Even if it's the password, it's not a server/client scenario, or interactive authentication, so why would we care about a timing attack?