Live data from Hacker News

German BSI withholds Truecrypt security report

golem.de

21–30 of 86 posts

Re: German BSI withholds Truecrypt security report

#21
post #2

Note, the title is no longer accurate. There's an update at the end of the article, along with a download link: > Shortly before we published this article the BSI has allowed to publish the Truecrypt documents. They can be downloaded from the Frag den Staat web page. Update from December 16th 2019, 13:22

This AP7 (work package 7) document seemed the most relevant, although most of it reads like generic test results and conceptual stuff. Not sure why they would try to hold that back. A non-malicious view would be that they simply are a part of German bureaucracy and subsequently slow.

Non-Google translation of the summary (AP7, page 70) for those interested:

"5 Summary

This work package first describes the basic building blocks that are utilized to secure the start [boot?] process, as well as ones that might be necessary and helpful to realize hard dism encryption via full-disk-encryption .

Beyond that existing attacks are described and investigated if the solutions presented here mitigate against them or not.

In chapter 4 several possible solutions are presented, both online (meaning with network connectivity) as well as offline.

The most promising solutions use the new Trusted-Computing functionality based on a Trusted Platform Module (TPM) and a Boot of Trust (CRTM/SRTM/DRTM).

The most desirable solutions are the Secure Boot procedure from chapters 4.4 and 4.5. These do however require either the development of new hardware or need to be based on special hardware extensions, e.g. Intel's TXT technology.

A large-scale deployment in an existing, heterogenous area is therefore improbable.

At the moment solutions that combine Trusted Boot with the attestation functionality seem to be the most sensible. This solution can be combined with: - Sealing: Storing a secret on the platform configuration. - NVRAM: Storing a secret in an area of the Trusted Storage, inside the TPM, that is only readable/writable given a valid configuration. - Attestation: Proof of platform integrity towards an external party. As "external parties", multiple counterparts could be realized: - Online, e.g. a central server. - Offline: e.g. a smart card or a smart phone application that takes on the verification for the server. All three variants (sealing, NVRAM, attestation) are reliant on the correctness of the PCRs."

The rest is potential use cases and an impact matrix of the attacks described in the document.

Re: German BSI withholds Truecrypt security report

#25
post #6
post #2

Note, the title is no longer accurate. There's an update at the end of the article, along with a download link: > Shortly before we published this article the BSI has allowed to publish the Truecrypt documents. They can be downloaded from the Frag den Staat web page. Update from December 16th 2019, 13:22

The documents seem to be available here: https://fragdenstaat.de/anfrage/untersuchungen-zum-verschlus... They all have "geschwärzt" (blackened) in the file name, but it looks like only some author's name (and maybe working group name) have been removed -- I've scrolled through a few of these files, and didn't find anything else that might have been removed.

I'm not sure if the implication of the following is that sections of the report were withheld or that it was incomplete to begin with.

> However the report hints that more such flaws exist. Another chapter in the documents mentions, that several such off-by-one-errors were found, but due to a lack of a complete code analysis only examples can be shown. However even those examples are missing in the document - the following chapter only consists of a headline and has no content.

Re: German BSI withholds Truecrypt security report

#27

Why would they release an audit that effectively provides them with zero-days into encrypted suspect disks. They release now because no one is using TrueCrypt any longer..

Because there weren't any real zero days in the report in the first place. The article mentions that it's mainly minor things like failing to clear memory, which is only helpful in rare circumstances.

Re: German BSI withholds Truecrypt security report

#28
post #13

"... in the simplest case a user can mount a Truecrypt volume that contains a file with suid root permission that will open a shell. Golem.de was able to replicate this scenario in a current version of Veracrypt."

This surprised me the most―never thought about this before. Aren't all permission-supporting filesystems vulnerable to this if mounting by a user is permitted? I presume filesystems don't go through the files and downgrade root ownership.

Re: German BSI withholds Truecrypt security report

#30
post #23
post #13

"... in the simplest case a user can mount a Truecrypt volume that contains a file with suid root permission that will open a shell. Golem.de was able to replicate this scenario in a current version of Veracrypt."

... if you have sudo.

Where does sudo come in with suid executables? Especially since afaik sudo depends on suid in the first place.
Post reply on HN