Another day - another cryptolocker infection

All too frequently we are still seeing people being affected by ransomware. It's pernicious and hard to get rid of once you've got it. If you haven't had it, then this is what happens - you open an innocent email and your computer starts to perform a bit sluggishly. Most people shrug this off then go to open a Word Document or Excel Spreadsheet and can't. It has .ENCRYPTED after it and there are files appearing in all your directories on how to pay to get your data decrypted. A sense of doom starts to build in the pit of your stomach and you watch as the files on your network drives start being encrypted too. Hopefully you pull the power plug and call your IT guy at this point. Then the tough stuff begins....

To stop this from happening here are some tips to keeping your PC cryptolocker free:

• don't try to open a zip file emailed to you - if someone is sending one to you, make sure they establish contact first - it's OK to email them back to ask if they meant to send it. Most companies won't send you a zip file with their bills in it - the AGL email that recently infected a number of people is an example of this. They send their bills as a PDF
• hover your mouse over any link in an email *before* clicking it - you'll see the actual address the hyperlink points to when you do this. Just because it says www.google.com/alkajsdflkjadf doesn't mean it actually points there. The hyperlink goes around the text to send it to the web and it could go anywhere!
• while backups are important, RESTORES are mandatory - a phrase I heard at SAGE-AU years ago and it's still true. There are great free options out there - from Time Machine on the Mac, to CrashPlan across many platforms, Carbonite, ShadowProtect and so on. Get one, have a backup to a USB drive, and then to another USB drive - a bit of a pain to cycle through the backups, but what is your data worth to you? It's a sad situation that most people won't have the faintest idea until every word document they've ever written is encrypted and carries an $800USD price tag to decrypt it. Put an entry in your calendar to backup and do it. 
• did I mention backups? Let me reiterate - back up your data! Test the backup! Have it disconnected from the network and don't rely on a single data storage place to back up to. If that gets corrupted (and I've seen it happen) - it's still all over
• go slower when you are readying your emails. Take your time to really check what you've got and why they want you to click on that shiny, interesting looking link. Phishing emails, cryptolocker and other infections are just a mouse click away....

It's a dangerous world, opening up an email program on your computer or a web browser. You never know where it will take you or the risks that it will entail. You can be safe, if you exercise some commonsense!

The rise of ransomware and the devil that is Cryptolocker

Over time, with advancements in anti-virus and anti-spyware, the ne'er do wells would eventually evolve. Their cunning and understanding of human behaviour has resulted in the devil that is ransomware. An innocent email from Australia Post arrives or a letter from the Australian Federal Police turns up in your inbox - most people are curious, even excited by an unexpected package, or concerned about a letter from the AFP and so they click the link. Boom! All their data starts to be infected - encrypted with heavy encryption and a lovely letter to say pay us or never get your stuff back.

We've seen it live and in the field on at least 5 occasions and had one or two clients actually pay the ransom - buying their Bitcoins and getting their decryption key back. Sadly, we've had people try this only to find out the website they need to talk to has been closed down by the authorities and their data irretrievably lost - until we restore it from backups that is... but sometimes even this doesn't work if people haven't moved data to the servers for backup. It's not good.

It seems like it was inevitable that a new mode of making money from people would have to emerge. Stealing credit card details and personal information - while profitable - is also fraught with danger of being identified when you try to use them. An anonymous ransom - helpfully supported by an anonymous currency - means a relatively straightforward exchange - a key for your own data back. It's kind of elegant in a way. This doesn't mean I don't think these people should be prosecuted - I've seen and experienced the stress and pain of business owners as their data becomes inaccessible and I'd love to pass that back to the perpetrators.

There are ways and means of protecting yourself from this, but it comes down to being systematic about it - just like these thieving bastards have been. Consider your vectors of risk:

• external influences
• email
• websites
• physical influences
• users
• dodgy USB keys
• active attacks
• hack attempts
• social engineering

There could be more.

Defending against these requires defence in depth. Some of these things are passive - they do the job all the time, with managed updates and some are active - people actually need to think about what's happening. Here are a few examples:-

• email scanning (externally if possible)
• strong firewall
• internet scanning (if possible)
• anti-virus and anti-spyware on the machines
• Chrome instead of good old IE (or awful Edge)
• user education - the single best form of protection and typically the one with the least amount of time and resources put into it. Honestly, it makes me experience sadness that people aren't trying to get their staff skilled up a bit on the computer. It doesn't take all that much!
• backups
• backups of backups offsite
• restorable backups

Of course, this kind of systematic approach doesn't just cover the awfulness of ransomware, but could be helpful against many other risks - attacks, environmental (fire / flood / famine / Justin Bieber), malicious employee activity (still identified as the Number #1 risk by many security dudes) and other "out of the box" issues.

I haven't mentioned patching or updating your system although I know this is critical. Updates are a beast of a thing, and anyone caught with a SharePoint update that means a database rebuild will feel where I'm coming from with this - security updates can cause more pain than if the damn thing was hacked or compromised in some way. Understanding the impact of an update on key infrastructure is very important and it isn't a passive security mechanism like some of the other things I've mentioned.

Reporting is also a tricky thing - yes it's great to have all this stuff going on, but who wants to plough through 20 or 30 system generated emails in a morning? I have for the last 12 years and it's bollocks. I don't care for it at all, and to be honest - it becomes so rote and routine that I miss things (sometimes very important things) because I'm just skimming. I urge you to consider some sort of consolidation report or webpage with information colour coded according to rules so that things going wrong are immediately obvious. We only have a limited attention time (and I think I've written about this elsewhere) and so we need to make sure that time is being carefully put to use and not wasted on stuff that's all OK and we don't care about. Likewise, with Nagios or other monitoring software I'm using, the thresholds for things going wrong is quite high - i.e. tell me when something is really going to be in trouble, not that it's just experiencing some sadness now. 

This post has diverged somewhat from cryptolocker, but the principles in keeping that piece of garbage out of your network are similar across a wide range of threats.