Archive for December, 2008

md5 SSL Certificates…not so secure?

December 31st, 2008

At a recent conference, it was announced that a group of researchers have been successful in creating bogus SSL certificates that will look legitimate to your browser. They did this through something known as md5 collisions. When SSL certificates are made, part of the process is creating an md5 hash associated with that certificate. Then, when you visit say amazon.com, your browser (the client) can check a locally generated hash against the certificate to confirm validity.

The problem with that is these hashes are NOT unique. There are “collisions” that can occur; two completely different files or strings or in this case certificates can have identical hashes. Through some massive computing power, researchers were able to create certificates that mimic the valid hash of certain websites which to say the least is dangerous for anyone visiting a compromised website. You could be redirected to a phishing website for your local bank and it would still look completely legitimate, SSL certificate and all.

People, this is why we have advancements in security. MD5 is a very old technology, and though still a good technology, it has been replaced by newer and better hash functions such as SHA-1 and SHA-2 to name a couple. Using MD5 to me is like saying that DES-56 encryption is good enough when you have AES-256 available to you. It is insanity for the websites that are dealing with the very security of our personal and financial information to not be using the latest and greatest technology.

To check out the presentation given at this conference, go here.

Dynamic Disks on a Laptop

December 30th, 2008

So a couple of months ago, the company I work for was interested in using a domain controller at a fairly large and important event that we conduct yearly. The idea was that rather than having to do last minute changes on about 120 laptops to accommodate various groups or needs, we could just push out any changes needed via group policy and save oodles of time. To keep things nice and mobile, we decided that a ThinkPad T61 would make an awfully nice mobile domain controller. We even threw in a second SATA drive into a removable tray so that we could have RAID-1 on our mobile DC. And that is when we hit the first snag.

Apparently, Microsoft deems it dangerous to be able to create dynamic disks and/or RAID arrays on laptops due to the “removable” nature of the media. In all fairness, I don’t really blame them – who in their right mind would set up a RAID array using a removable drive on a laptop? Well, that’s exactly what we needed to do. » Read more: Dynamic Disks on a Laptop

Multi Protocol Label Switching (MPLS) VPN

December 30th, 2008

Challenge Lab #1 – MPLS VPN

.

Overview:

.

A customer at XYZ corporation has just asked you, an engineer at HyperGlobalMegaCorp Regional ISP, to set him up a tunneled VPN connection between two of their sites. The problem is that somehow both XYZ and ABC corporations use the same exact IP addressing scheme, so they need to somehow accommodate that. You’ve been tasked with researching and implementing MPLS VPNs and VRF in order to accommodate both their security and IP addressing needs.
» Read more: Multi Protocol Label Switching (MPLS) VPN

DNS SRV Entries

December 29th, 2008

So over the past few days, I’ve been trying to hack together a setup at my home for this website using an old Thinkpad T41 on my cable modem connection (yea…I didn’t think I’d need a ton of bandwidth…yet!). Of course port 80 and 443 are blocked by default since Optimum Online doesn’t want us hosting servers on a non-business account, so I was running this on port 85 and 886 for HTTP and HTTPS respectively. Simple right? Yes, up until you try to make DNS work all nice and pretty (a.k.a. no port numbers needed in the address).

An absolutely perfect solution to this dilemma would have been DNS SRV entries. Or they would have been if any browser in existence supported them. I can’t really fathom why they aren’t supported either.
» Read more: DNS SRV Entries