Oct 29, 2014

It's time to re-key your SSL certificates if they're signed with SHA-1

Google announced back in September that they will be the major catalyst for killing off SHA-1 around the world. In their blog post they talk about their plan to gradually "sunset" SHA-1 because of how weak it is.

From their blog:
The SHA-1 cryptographic hash algorithm has been known to be considerably weaker than it was designed to be since at least 2005 — 9 years ago. Collision attacks against SHA-1 are too affordable for us to consider it safe for the public web PKI. We can only expect that attacks will get cheaper.

That’s why Chrome will start the process of sunsetting SHA-1 (as used in certificate signatures for HTTPS) with Chrome 39 in November. HTTPS sites whose certificate chains use SHA-1 and are valid past 1 January 2017 will no longer appear to be fully trustworthy in Chrome’s user interface.
That's right, starting next month if your website is using an SSL certificate that was signed with SHA-1 and is good past January 2017, then users that browse to it with Google Chrome will start getting browser warnings! Thanks Google!

That means you need to have your certificates re-keyed through your SSL provider using a certificate signing request (CSR) with a SHA-256 signing hash if you don't want people to get browser warnings.

If you use IIS, even in Windows 2012 R2, it will still generate a CSR with SHA-1 only. So you need to use OpenSSL to generate your CSR. Linux has it built in, but if you are a Windows server user you can download a Windows version.

To generate your SHA-256 CSR run the following:

openssl req -nodes -sha256 -newkey rsa:4096 -keyout PrivateKey.key -out CertificateRequest.csr

You will prompted for the usual information, and this will create your private key and your CSR to send to your SSL provider. Once your new cert is issued you should be good to go if you have an Apache server or Nginx.

If you are a Windows IIS user you may want to create a p12 file with your certificate and private key all in one file so you can easily import it with the Certificates MMC snap-in. To create the p12 file run the following command:

openssl pkcs12 -export -in SignedKeyFromCA.cer -inkey PrivateKey.key -out SignedKeyPair.p12

You will be asked for a password to protect your key and you'll have to remember that password when importing it into Windows.

That's it, once that is done and installed you can check to make sure you did everything properly with SSL Labs.

Oct 22, 2014

I'm switching back to OpenSSL on my Ubuntu Apache Servers

Many moons ago I posted about how I switched from OpenSSL to GnuTLS. That was because I wanted to mitigate against The BEAST attack, and at that time the version of OpenSSL that came with Ubuntu didn't support TLS 1.1 or TLS 1.2.

Well, in the latest Ubuntu releases OpenSSL does support it, but the funny thing is that something is wrong with GnuTLSPriorities in Ubuntu 14.04. For some reason, the string doesn't work anymore and I can't so simple things like disable SSL 3.0 which you need to do to mitigate against the new POODLE vulnerability.

I decided to switch back to OpenSSL, and in order to be PCI compliant and get an A+ rating on SSLLabs.com I also added the following to my /etc/apache2/sites-enabled/default-ssl.conf file:
SSLCipherSuite AES256+EECDH:AES256+EDH
SSLProtocol All -SSLv2 -SSLv3 -TLSv1
SSLHonorCipherOrder On
Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"
Header always set X-Content-Type-Options nosniff
You need to be sure that you have headers enabled for the above to work.

Once all of that is done you should be good to go!
[Code via Cipherli.st]

Oct 1, 2014

Alternative To Truecrypt and Bitlocker For Full Disk Encryption

Cryptographically secure pseudorandom number g...
 (Photo credit: Wikipedia)
We all know that the original creators of Truecrypt jumped ship and instead of passing on the source code decided to make the latest version that will only decrypt, but not create new encrypted volumes. They also spouted some nonsense about how it is no longer safe.

Well, a new group has taken over the project but we don't know when they will have a new release out. Because of that some people don't want to use Truecrypt anymore and are looking for alternatives.

One I'm trying out now looks promising. It is called DiskCryptor. Here are the features from their page:

·         Support for encryption algorithm AES, Twofish, Serpent, including their combinations.
o   Transparent encryption of disk partitions.
o   Full support for dynamic disks.
o   Support for disk devices with large sector size (important for hardware RAID operation).
·         High performance, comparable to efficiency of a non-encrypted systems.
o   Support for hardware AES acceleration:
o   AES-NI instruction set on new Intel CPU;
o   PadLock extensions on VIA processors.
·         Broad choice in configuration of booting an encrypted OS. Support for various multi-boot options.
o   Full compatibility with third party boot loaders (LILO, GRUB, etc.).
o   Encryption of system and bootable partitions with pre-boot authentication.
o   Option to place boot loader on external media and to authenticate using the key media.
o   Support for key files.
·         Full support for external storage devices.
o   Option to create encrypted CD and DVD disks.
o   Full support for encryption of external USB storage devices.
o   Automatic mounting of disk partitions and external storage devices.
·         Support for hotkeys and optional command-line interface (CLI).
·         Open license GNU GPLv3.

The one thing it is missing that I used a lot with Truecrypt is the ability to make encrypted file containers which are great for keeping files encrypted over shared file storage like Google Drive. For full disk encryption though it works like a charm.

A thing that I liked about Truecrypt was you could easily install it on a Linux Live CD so you could perform offline maintenance if you needed to with an encrypted volume. Well you can't create a Linux Live CD for DiskCryptor, but you can create a WinPE live disk with it!

So far it looks good, and I boot up time doesn't appear any more impacted than it did with Truecrypt. For now, I think this one might be my choice for the best alternative.

What are you using for full disk encryption since Truecrypt went belly up for the time being? Let us know in the comments.

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