Blast from the past

Since I've been talking about game security the last couple of posts. I figured I revisit an old target I once investigated.

Many many moons ago I blogged about getting Dark Age of Camelot to run in wine. While reversing that game, I also had a look at how the actual game connection works, because that's something that always interests me, ie. the security aspect of it. In this case, there was an extra reason to have a look, since at one time early on in the game's life, a security issue was found and reported to them:

CVE-2004-1855
Dark Age of Camelot before 1.68 live patch does not sign the RSA public key, which could allow remote malicious servers to gain sensitive information via a man-in-the-middle attack.
A more detailed description is available at:
http://capnbry.net/daoc/advisory20031211/daoc-billinginfo-exploit.html

So fast forward 10 years, you'd think it would be pretty secure by now... unfortunately it appears it's still flawed in some way. The thing is, even after all these years, the game is still susceptible to a man-in-the-middle attack. It's perfectly possible to intercept / proxy a connection from the game without needing any details / account info from the player.

So how does the game connection work?

The communication is rather straight forward. There's only 1 connection maintained between the client and the server. The game supports both UDP or TCP for it's game session. This probably stems from the old days where most players actually used a dialup connection, where you don't want TCP retransmissions to cause issues.

Most of the game packets are known. There has been an emulator around for quite some time now and since it's open source, anyone can have a glimpse at how it all works.

The connection is encrypted with RC4. It generates a random session key which gets exchanged via RSA encryption. The generation of the RC4 key could also be improved, since how it currently is done, makes it extremely easy to intercept by using some virtualization techniques. This has as effect that one can get the game to generate the key you want, without having to make any patches to the game client, which is imho not a good thing.

But worse is the fact that this all doesn't matter, due to another vulnerability. But before explaining that one, I'll see if there's still anyone in charge of the game code (most players of the game, seem to think the janitor is the only guy left in the building.. so we'll see how it goes)

Anyway, let's hope the old Mythic gang @ City State Entertainment will have a better security track record if their Kickstarter project, Camelot Unchained, funds!