Ransomware prevents Windows from starting by replacing the master boot record

Ransomware asks users to pay up before letting them start Windows

A new ransomware variant prevents infected computers from loading Windows by replacing their master boot record (MBR) and displays a message asking users for money, according to security researchers from Trend Micro.

"Based on our analysis, this malware copies the original MBR and overwrites it with its own malicious code," said Cris Pantanilla, a threat response engineer at Trend Micro, in a blog post on Thursday. "Right after performing this routine, it automatically restarts the system for the infection take effect."

The MBR is a piece of code that resides in the first sectors of the hard drive and starts the boot loader. The boot loader then loads the OS.

Instead of starting the Windows boot loader, the rogue MBR installed by the new ransomware displays a message that asks users to deposit a sum of money into a particular account via an online payment service called QIWI, in order to receive an unlock code for their computers.

"This code will supposedly resume operating system to load and remove the infection," Pantanilla said. "When the unlock code is used, the MBR routine is removed."

As the name implies, ransomware applications hold something belonging to the victim in ransom until they pay a sum of money. This type of malware is considered the next step in the evolution of scareware, malicious programs that scare users into paying money.

The majority of ransomware applications disable important system functionality or encrypt documents and pictures, but this is the first ransomware program that Trend Micro researchers have seen replacing the MBR to prevent the system from starting.

This represents a serious escalation in ransomware techniques. While users can still run security tools to clean their systems of traditional ransomware applications and even recover some files, if Windows doesn't start at all, like in this case, the remediation procedure becomes much more difficult.

Repairing the MBR is no trivial matter and usually requires booting from the Windows installation disk, getting into the recovery command console and typing special commands.

Ransomware infections are typically more common throughout Eastern Europe and South America, but this type of malware is slowly gaining traction in other regions of the world as well. Some variants that impersonate law enforcement agencies and ask victims to pay fictitious fines have recently been detected in Western Europe.

"Though overshadowed by other more newsworthy threats, ransomware attacks are definitely not out of picture. In fact, this threat appears to be flourishing, as evidenced by the growth of ransomware infections in other parts of Europe," Pantanilla said.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Lucian Constantin

Lucian Constantin

IDG News Service
Show Comments

Brand Post

Shining a light on creativity

MSI has long pushed the boundaries of invention with its ever-evolving range of laptops but it has now pulled off a world first with the new MSI Creative 17.

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?