Monday, 14 December 2009

Linux secure?

Oh my, read this; http://www.omgubuntu.co.uk/2009/12/malware-found-in-screensaver-for-ubuntu.html
Of course this is just the beginning, I saw this in the early days of windows, popularity means people want flashy yet lame screensavers so they go a hunting, see a banner ad that is flashing epileptically at the user that tells them their search is over, they click it and install a new theme for their cursor (I hate these), a day of the month screen saver, or a fancy toolbar which will let you know who is browsing your MyFaceTwitLinked page at any given time, and also automatically installs thousands of other applications you may like, hiding in these are some nice little bots. Of course on install it asks them for their password as it has to make system changes, it then puts a helper in roots cron and makes a new init.d daemon to keep it memory resident and its privledges elevated, heck maybe it even recompiles some binary that is used frequently with elevated privledges that checks all that other stuff is still good to go, something like the logserver or init
Then we Linux will have reached the popularity of windows, the weakest link will again be the user.
So in my humourous little story above I am trying to point out just cause it is safe now won't mean it will be forever. Windows is less and less about Worms that automatically get in without user intervention. Conficker was the last big one and MS had a patch out before it hit, so it was only slow patching that really let it spread. The rest of the viruses that are seen are delivered along with innocuous looking software, or at worst a drive by download that means a page is running something in the background that takes advantage of a hole in internet explorer to install something, these drive by downloads won't happen. But have a look at the top 15 http://www.net-security.org/secworld.php?id=8597 most common attacks and you will see Linux and Macs are susceptable to the lot, through misconfiguration or user error.
Don't get me wrong I am a big Linux fan-boi. If I had it my way Windows would be the struggling niche, Linux would have 96% market share, BSD 2% and macs wouldn't exist :P I think the ideal behind linux is very admirrable and scientific. Linux builds on what has come before it (usually) and because what has come before is open and readable this is fairly easy. "If I have seen further, it is by standing on the shoulders of giants." Sir Isaac Newton. To not build on what has come before is to repeat your predecessors mistakes.
There will always be flaws, till we write code that can write its own code it may eventually create something almost flawless, or one of its children will.
I think Linux allows for greater security, but also greater insecurity. Security is not where open sources power lies, it is its flexability.

Tuesday, 17 November 2009

Rickrolling has gone viral again

Now this story interests me on so many levels.
It has put Wollongong on the map again people. I'll admit I was raised in the Gong, so it is good to see someone even making notoriety that is from Wollongong. The last renowned intelligent export we had was Evelyn Owen or Sir Lawrence Hargrave (1939 and 1915 respectively) so it has been some time between.
I also dislike apple, there practices annoy me; there practice of dumbing down everything even the extremely technical is the same as dropping superfluous words from the English language to make it easier for speakers, we only need one word for cold right? They also stand on the shoulders of giants, yet give little recognition to those. Yes they made Unix "usable" (so did Linux without the pompousness), but try and find their references of gratitude to all their stolen code, or stolen ideas, nope. Apple have fallen down in the security world repeatedly, and this is a glaring example who sets the same password on every device when you can assume with pretty high certainty that people are going to attack it and find out your password, hence the unlocking.
The other reasons this is interesting is it is a virus that Rickrolls people, hilarious. Rickrolling is something I have done, and had done to me a fair few times, it almost always makes me smile. The other humorous point of this is the author is Ashley Towns, so the meme of Rick Astley is almost made for him.
Well if you own an iphone (hisss) then you can secure it against this virus here(a simple passwd to fix it), bear in mind that this virus will probably hang around for a few years like code red and slammer, funny stuff.

Wednesday, 2 September 2009

Revocation, just rolls off the tounge

First an overview, SSL is pretty much the only protection available when banking, shopping etc. It means the user has to look for the https:// up the top rather than the http:// to ensure the session from their browser to the websites server is encrypted in transit (this isn't perfect people can fake some certificates, and security researchers are trying to find its holes all the time). Don't trust the lock or the little green bar that EV certs give you as these can be faked several ways, generally though the https and certificate information can be trusted. Also look at an extension for FireFox called SSL blacklist for FireFox that will notify you if a certificate is bad due to one of many reasons.
One of the interesting things about certificates is of course they have to be able to be revoked, when for some reason they become compromised or some such other reason.
CRL or certificate revocation lists as some are probably aware are basically a list stored on the company that provided the certificates website, basically a list of all the certs that have been revoked. Excellent idea, but look at most certificates details and CRL is hosted on a good ole plain http site eg; http://crl.thawte.com/ThawteSGCCA.crl
YAY, so if you want just own a few crl via DNS poisoning or man in the middle (MITM) a user (can we say web cafe) and serve up a fake crafted CRL to revoke heaps of certificates or just remove your revoked cert for their bank etc. Of course there are a lot of variables here, you need to know the CRL that is going to be requested though if you have MITM'd them you can just serve all of them up, they are usually signed, but not always, you also need to know sites they are going to go to, but you can dynamically do this as well.
Their digital signing doesn't look that good from what I have seen from reading the crl's either, but they are supposed to sign it with their SSL certificate available from their site via a link, so no trust their just sign it with your own cert and serve that up at their site as you are already in the middle.
But the nice thing as far as a denial goes is that most operating systems cache this info (for 24 hours usually), and the Certificate hierarchy is good just blacklist the vendors root certificate.
To do any real damage you still need to get a certificate registered that has been falsely registered, or do a bit of social engineering, blacklist all certs and pop up a page saying the user needs to update their certificates, redirect them to a legit looking site that asks them to install a certificate package full of your own generated root certificates, all SSL sites from then on are readable as you re-sign them with your key on the way through.
Of course SSL isn't a fix for the revocation lists as no one will see that it requests the list from https instead of http, I have even seen some installs of Internet Explorer that have certificate revocation checking turned off, I am not sure if this is default, but bad none-the-less.

Well I hope this long winded odd rant is at least made some people think. It is a very odd setup and I am surprised all CRL's don't require possibly multiple signing by at least two vendors kind of like nuclear launch codes.

Wednesday, 24 June 2009

Vmware issues

Not so much a dedicated security issue (though Availability is in the CIA triangle that should be drummed into everyone by now), but something I thought I would blog about as I found it no where else.
I was having an interesting issue with a guest on one of the ESX clusters I manage, looking at the ESX host, none of its other guests were having issues. The guest in questions came up as disconnected, not powered on. But I could RDP to it.
I logged into the host and checked esxtop and noticed the Guest was in the list.
Checking the tasks of the Guest in the Vmware client I noticed its VCB backup last night died, and that the error I was getting on the guest was Unable to communicate with host, since it is disconnected, I got this same message when trying to power on the guest.I quickly checked the vmware.log and dmesg on the ESX host that was hosting the guest, nothing obvious, googling around gave me no answers. It was then I noticed the last entry in the vmware.log was early this morning, to do with CD rom errors. I thought it could be a simle management disconnect, so I ran

/etc/init.d/mgmt-vmware restart
The whole ESX server disconnected from the VMware client as you expect, then it came backup, the problem host came backup too, no downtime, no mess. Ran a quick manual backup and all done.

Friday, 2 January 2009

Ruxcon belated Day2

So this is really a belated day2, been fairly busy at work. We had an embargo for changes over December, but that didn't mean we didn't do work, we had less people on so we did more.
I am going to put a bit more in that the initial recap I did of day 1, first the recap of Day2.
Day 2 was well and truly on par with Day 1, the Ruxcon guys put on an awesome con, and I had a great time.
To recap on day two I went first to an excellent talk by Ben Mosse entitled Browser Rider, next on to a promising tool that was presented I thought somewhat appethetically called Intelligent Webfuzzing by Neil and Bern Archibald. Then onto the BBQ lunch where I had a chat with one of my security mentors the venerable Martin Visser (he knows his wireshark fu).
Then after lunch I went to one of the highlight talks of the con, Netscreen of the Dead by Graeme Neilson (that I recently heard talked about on the pauldotcom security weekly podcast). Then onto the smaller room2 for Googless by Christian Heinrich a fairly good talk but I think aimed more at those not up on their google fu and scripting.
Then finally onto a very interesting talk by Adam Daniel called Pimpin: Forensic Style.

NOTE the talks slides (not videos yet) are available here

I was going to talk about the day in more depth, but that has been whats has delayed this. I will post my notes one day.