CVE-2014-0160, better known as the Heartbleed bug, it a critical, easily exploited, and widespread bug in the OpenSSL library that powers many HTTPS implementations around the world.

It is a memory leak exploit that can be used to potentially expose server keys, and any amount of other private information, so, it’s hard to stress exactly how important it is that you patch your servers now!

Because it may help others, here’s what I did:

Diagnosis

First step is to confirm that your servers are vulnerable. The vulnerability exists in OpenSSL libraries newer than 0.9.8 and persists until fixed in 1.0.1g. This means it is present in both Debian stable and Ubuntu systems, among others.

You can confirm whether your systems are vulnerable with this handy python program (mirror on gist), written by Jared Stafford, which attempts to exploit this bug.

Fixing

  • Debian and Ubuntu users should apt-get update; apt-get upgrade as soon as possible, since the security team has already patched the vulnerability. Other distros are likely to do the same, and I wouldn’t be surprised if patches were already released.
  • If your distro hasn’t patched yet, or you’ve compiled your own code, you should update to 1.0.1g now, or recompile your current OpenSSL binary with the -DOPENSSL_NO_HEARTBEATS. option set.

Thankfully, I run Debian, so my fix was easy. However, it is important to highlight that after updating the library you must RESTART any services that make use of it, notably Apache in my case.

This seems obvious, but until you do this your server is still vulnerable, so it’s worth underlining, and it caught me out!

Verification

Finally, it is important to verify your fix (how I spotted the restart requirement!). Use the same python tool above, and you should see something like:

marcus@dushka:~$ python ssltest.py marcus-povey.co.uk
Connecting...
Sending Client Hello...
Waiting for Server Hello...
 ... received message: type = 22, ver = 0302, length = 58
 ... received message: type = 22, ver = 0302, length = 3527
 ... received message: type = 22, ver = 0302, length = 781
 ... received message: type = 22, ver = 0302, length = 4
Sending heartbeat request...
Unexpected EOF receiving record header - server closed connection
No heartbeat response received, server likely not vulnerable

Happy patching!

Update: seems that lots of people must be after that python script, as we seem to have killed the poor guy’s server. I’ve stuck a copy of it on Gist, hopefully Jared won’t mind!

This is a quick post to introduce you to a little plugin I wrote for wordpress, wordpress-idno-feedwidget.

The plugin creates a wordpress widget that lets you display the latest content from your Idno site in your blog sidebar. It’ll render the first 50 characters of a status update, and the titles of blog posts, with an author picture and a link to both the author profile and original posting. Image posts are also rendered, with a thumbnail view (although this could be made more efficient).

There is plenty of room for improvement; I’d like to render different types better, videos and events with an appropriate player for example, but it’s a start! The widget makes use of the JSONP endpoint, so make sure you’re using the latest codebase.

» Visit the project on Github...

GCHQoogle: so much for "Don't be evil"Given what we now know about the mass surveillance, and attack on the infrastructure of the internet, conducted by Britain’s GCHQ and America’s NSA (as well as their Chinese, Russian, German, etc counterparts).

Given that we now know, for a fact, that almost every byte of non-encrypted traffic is recorded and analysed, shouldn’t we now make a concerted effort to finally deprecate vanilla HTTP in favour of HTTP over TLS (HTTPS)?

When you use HTTP, it is a trivial matter for an attacker to see the content of the pages you visit, when, and how often you visit them. When using HTTP, there is also no guarantee that the content of the page hasn’t been modified without your knowledge, exposing you to all kinds of attacks.

Encryption, by and large, removes these problems, as well as massively increasing the cost of mass surveillance. Is it not time for all of us, as well as standards organisation like the IETF, push to make HTTPS the default? Even during my time I’ve seen insecure protocols like telnet and FTP go from widespread use to being almost completely replaced by secure alternatives (ssh and scp), so could we not do the same with HTTP?

Certificate authorities

Ok, there is one big difference between HTTPS and ssh (ok, many many, but one I care about here), and that is that HTTPS relies on certificate authorities. These are necessary in order to distribute trust, so that browsers can know to automatically accept a certificate and verify the server it is connecting to is who it says it is.

This is much nicer for the average user than, say, manually verifying the server’s fingerprint (as you have to do with SSH), but comes with some pretty serious problems if we were to make it default:

  • Every site owner would have to get a certificate, and these can only be obtained by a certificate authority if you don’t want browsers to pop up a big red warning, meaning we further bake these guys in to the Internet’s DNA.
  • Certificate authorities can be directly pressured by governments, so, a government attacker could MITM you on a secure connection and present you with a certificate that your browser accepts as valid, and so will give you no warning (of course, this is much more costly than the blanked mass surveillance that is currently going on).
  • Getting a certificate either costs money, and/or has restrictions placed on their use (for example, no commercial use, in the case of StartCom). This is really bad, since it essentially requires permission from a third party to launch a site.

It is this last causes me most concern, since it essentially provides an easy way of suppressing minority views.

Imagine that we lived in a world where HTTP had been deprecated, and browsers no longer supported unencrypted HTTP, or could, but you had to request it specifically (essentially the reverse of what we currently have). You wanted to launch a site that expressed a minority view – perhaps you were critical of your government, or you wanted to leak some information about crimes being committed, is it not inconceivable that you could have trouble obtaining a certificate? Given that certificate authorities are companies who worry about their bottom line, and are a convenient point for the bad guys to apply pressure?

If you couldn’t get a certificate in this environment, it could dramatically reduce the audience that would see your site.

So, perhaps before we move to deprecate HTTP, we must first find a better way than certificate authorities to distribute trust? How could we accomplish this? Perhaps we could take advantage of the fact that most people’s browsers automatically update, and so we could distribute browsers with expected certificates for sites hard coded into them (giving an added advantage that we could pin certificates)?

Anyway, its complicated, and I’m thinking aloud here… what are your thoughts?