To Stop Cryptolocker, Think Like Cryptolocker

Dane Meah
August 24, 2016


Cryptolocker is here and getting nastier

CryptoLocker and other variants of Ransomware are spreading like wildfire in the cyber security world. Ten years after it first appeared in Russia, four million samples of Ransomware were identified in the second quarter of 2015 alone.

Today the global variety and scope of Ransomware is exploding – moving away from advanced technical attacks towards criminal business models with a large funding base. Ransomware outfits now have budgets for marketing, ‘customer support’ and streamlined operational efficiency.

According to Security Magazine, Ransomware is beginning to target the Internet-Of-Things. Meanwhile Ransomware-as-a-Service has emerged for fraudsters and criminals looking to use stolen data as a threat.

Sounds scary and in many ways it is. The attackers are getting bolder and their attacks more sophisticated.

CryptoLocker is particularly interesting as it transgresses several security architecture ingress points. But you can prevent or mitigate the effects of a Ransomware attack with some simple changes to your IT Security posture.

There’s no silver bullet but with a little attention and tweaking, and a clear and thorough process, you can help protect your network, users, data and ultimately your company’s bottom line.

How do you fight CryptoLocker?

First, think like Cryptolocker.

CryptoLocker preys on the good-will of the unsuspecting victims, using little-known back doors that exist in almost every network. It uses unscrupulous tactics to tug at the emotions, tricking everyday people into inadvertently bypassing security controls.

Second, understand how cryptolocker attacks your system.

At InfoTrust we’ve mapped out the end-to-end CryptoLocker lifecycle against the Cyber Security Framework from the National Institute for Standards & Technology (NIST).

The life-cycle of a successful CryptoLocker attack goes something like this:

  1. A Spoofed Email is delivered imitating a genuine organisation with a trusted brand (e.g. AusPost, AFP, etc…)
  2. This email arrives inbound, successfully bypassing your Email Gateway
  3. Your End User falls for the fraudulent email, usually by clicking a link to a “clean” site, which requires a human to enter the CAPTCHA codes to download the file
  4. The file passes through your Web Gateway anti-malware filters without detection.
  5. The malware executes, undetected by your Endpoint Security. The CrytoLocker quietly begins encrypting your files and propagating across your network
  6. You have no automated detection for this kind of activity
  7. When you finally realise you’ve been compromised, it’s too late. Thousands if not millions of files are encrypted and you have no Incident Response plan documented to deal with this scenario.
  8. With mass infection you attempt to recover using backups, but the recovery time of such a large volume of data takes days, causing downtime and lost productivity.
  9. The backup recovery point was over twenty four hours ago. One day’s work is unrecoverable and potentially lost forever.

Securing your Cryptolocker readiness means reviewing and improving these nine cyber security capability dimensions.

What can you do to protect against cryptolocker?

Typically you need only make simple (and in many cases free) configuration changes to prevent or mitigate CryptoLocker. But where do you start?

As a first step, our team can perform an audit, which will provide an insight into potential weaknesses in your security posture that CryptoLocker could exploit. Contact us for more information.