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Pwncloud – Bad crypto in the Owncloud encryption module

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Re: Pwncloud – Bad crypto in the Owncloud encryption module

#21

Post by giovannibajo1 »

drdaeman wrote: post #8
fapjacks wrote: post #3

Earlier quoted context omitted.

I just want to add a big emphasis to "YOUR OWN CRYPTO" with Dropbox. Stuffing data into Dropbox without encrypting it first for example with VeraCrypt is a bad choice. Even Dropbox says their own employees "need" access to your data "occasionally". (Also, I meant to upvote you but I fat-fingered it on my phone, sorry!)

VeraCrypt or other FDE-like tools (that are meant to be used on actual drives or their imitations using a file-backed device) are not so great idea for use with Dropbox or alike file/object storages. Here's why: http://sockpuppet.org/blog/2014/04/30/you-dont-want-xts/

Is there a client side encryption tool that works with Dropbox and is usable by non technical people (plus for being available on both Windows and Mac)?

I personally use encfs to create a partition within Dropbox, but I don't see that being easy to setup and manage...

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#22

Post by dublinben »

giovannibajo1 wrote: post #21
drdaeman wrote: post #8

Earlier quoted context omitted.

VeraCrypt or other FDE-like tools (that are meant to be used on actual drives or their imitations using a file-backed device) are not so great idea for use with Dropbox or alike file/object storages. Here's why: http://sockpuppet.org/blog/2014/04/30/you-dont-want-xts/

Is there a client side encryption tool that works with Dropbox and is usable by non technical people (plus for being available on both Windows and Mac)? I personally use encfs to create a partition within Dropbox, but I don't see that being easy to setup and manage...

EncFS is specifically not safe to use in situations where an attacker has multiple versions of your data.

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#23

Post by bigiain »

schlowmo wrote: post #9
fapjacks wrote: post #3

Earlier quoted context omitted.

I just want to add a big emphasis to "YOUR OWN CRYPTO" with Dropbox. Stuffing data into Dropbox without encrypting it first for example with VeraCrypt is a bad choice. Even Dropbox says their own employees "need" access to your data "occasionally". (Also, I meant to upvote you but I fat-fingered it on my phone, sorry!)

Yes, maybe I should've made this emphasis stronger in my comment. Also I didn't meant to say that using owncloud is worse than using dropbox in security terms - but you should use your own (client-side) crypto either way if you care about data security. For myself I use my selfhosted owncloud (running on a cheap VPS) with EncFS, encourage other users on that server to use client-side encryption as well and never lied…

I also use EncFS - on Dropbox/GoogleDrive/JottaCloud - but be aware it's got known flaws, don't rely on it if your data might be of interest to a nation state or high level law enforcement: https://defuse.ca/audits/encfs.htm

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#24

Post by netheril96 »

drdaeman wrote: post #8
fapjacks wrote: post #3

Earlier quoted context omitted.

I just want to add a big emphasis to "YOUR OWN CRYPTO" with Dropbox. Stuffing data into Dropbox without encrypting it first for example with VeraCrypt is a bad choice. Even Dropbox says their own employees "need" access to your data "occasionally". (Also, I meant to upvote you but I fat-fingered it on my phone, sorry!)

VeraCrypt or other FDE-like tools (that are meant to be used on actual drives or their imitations using a file-backed device) are not so great idea for use with Dropbox or alike file/object storages. Here's why: http://sockpuppet.org/blog/2014/04/30/you-dont-want-xts/

Time to promote my project `securefs` again (https://github.com/netheril96/securefs). Written specifically to address that XTS issue.

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#25

Post by JohnIcare »

schlowmo wrote: post #2

> "First it is important to understand what this encryption module is actually supposed to do and understand the threat scenario. The encryption provides no security against a malicious server operator, because the encryption happens on the server. The only scenario where this encryption helps is if one has a trusted server that is using an untrusted storage space." While it's a good finding that even in this specifi…

There is seafile ( https://www.seafile.com/en/home/ ) which provides client side encryption.

Easy to install and to upgrade (except a small glitch in the last upgrade).

For the community version, the source code is here : https://github.com/haiwen/seafile (see others haiwen projects).

The Android client could be improved, but it does the job.

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#26

Post by dchest »

JohnIcare wrote: post #25
schlowmo wrote: post #2

> "First it is important to understand what this encryption module is actually supposed to do and understand the threat scenario. The encryption provides no security against a malicious server operator, because the encryption happens on the server. The only scenario where this encryption helps is if one has a trusted server that is using an untrusted storage space." While it's a good finding that even in this specifi…

There is seafile ( https://www.seafile.com/en/home/ ) which provides client side encryption. Easy to install and to upgrade (except a small glitch in the last upgrade). For the community version, the source code is here : https://github.com/haiwen/seafile (see others haiwen projects). The Android client could be improved, but it does the job.

This issue in Seafile was lovely:

https://github.com/haiwen/ccnet/issues/35

   /* truly random sequece read from /dev/urandom. */
   static unsigned char salt[8] = { 0xdb, 0x91, 0x45, 0xc3, 0x06, 0xc7, 0xcc, 0x26 };
https://github.com/haiwen/seafile/issues/587

Enough to understand if people writing this software know how to apply cryptography. This was 2 years ago, so I hope they improved.

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#27

Post by microtonal »

schlowmo wrote: post #2

> "First it is important to understand what this encryption module is actually supposed to do and understand the threat scenario. The encryption provides no security against a malicious server operator, because the encryption happens on the server. The only scenario where this encryption helps is if one has a trusted server that is using an untrusted storage space." While it's a good finding that even in this specifi…

Bittorrent Sync does end to end encryption, and you can set up an encrypted read-only peer that never sees any plain text. The encrypted peer does contribute to the swarm.

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#28

Post by g_p »

giovannibajo1 wrote: post #21
drdaeman wrote: post #8

Earlier quoted context omitted.

VeraCrypt or other FDE-like tools (that are meant to be used on actual drives or their imitations using a file-backed device) are not so great idea for use with Dropbox or alike file/object storages. Here's why: http://sockpuppet.org/blog/2014/04/30/you-dont-want-xts/

Is there a client side encryption tool that works with Dropbox and is usable by non technical people (plus for being available on both Windows and Mac)? I personally use encfs to create a partition within Dropbox, but I don't see that being easy to setup and manage...

Cryptomator [1] looks like it fits the bill for what you described. Seems to use a transparent mapped virtual WebDAV drive to make it usable. From my experiments at least, it seems it should be usable by non-technical people without significant demonstration or training.

[1] https://github.com/cryptomator/cryptomator

Re: Pwncloud – Bad crypto in the Owncloud encryption module

#29

Post by Artemis2 »

dchest wrote: post #26
JohnIcare wrote: post #25

Earlier quoted context omitted.

There is seafile ( https://www.seafile.com/en/home/ ) which provides client side encryption. Easy to install and to upgrade (except a small glitch in the last upgrade). For the community version, the source code is here : https://github.com/haiwen/seafile (see others haiwen projects). The Android client could be improved, but it does the job.

This issue in Seafile was lovely: https://github.com/haiwen/ccnet/issues/35 /* truly random sequece read from /dev/urandom. */ static unsigned char salt[8] = { 0xdb, 0x91, 0x45, 0xc3, 0x06, 0xc7, 0xcc, 0x26 }; https://github.com/haiwen/seafile/issues/587 Enough to understand if people writing this software know how to apply cryptography. This was 2 years ago, so I hope they improved.

https://xkcd.com/221/
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