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Windows Vulnerability - WannaCry Ransomware

Ransomware is a malicious software that encrypts files and locks devices, such as a computer, tablet or smartphone and then the attacker demands a ransom to unlock it.

Recently, a dangerous ransomware named Wannacry has affected devices worldwide creating the biggest ransomware attack the world has ever seen.

The trojan stores encrypted data on your device's disk such that you can no longer access your own data, thereby blocking normal access to your device. The most common ways in which WannaCry Ransomware is getting into user devices is via phishing emails which lures you to click a link in an email to visit a website that contains a malicious program.

What is WannaCry Ransomware?

WannaCry ransomware attacks Windows based machines. It also goes by the name WannaCrypt, WannaCry, WanaCrypt0r, WCrypt, and WCRY. It leverages SMB exploit in Windows machines called EternalBlue to attack and inject the malware. All versions of windows before Windows 10 are vulnerable to this attack if not patched for MS-17-010.

After a system is affected, WannaCry encrypts files and shows a pop up with a countdown and instructions to pay the USD 300 in bitcoins to decrypt and get back the original files. If the ransom is not paid in 3 days, the ransom amount increases to USD 600 and the attacker threatens the user to wipe off all the data. It also installs DOUBLEPULSAR backdoor in the machine.

How it spreads?

WannaCry uses EternalBlue MS17-010 to propagate. The ransomware spreads by clicking on links and downloading malicious files over internet and email. It is also capable of automatically spreading itself in a network by means of a vulnerability in Windows SMB. It scans the network for specific ports, searches for the vulnerability and then exploits it to inject the malware in the new machine and thus it spreads widely across the network.

What can you do to prevent infection?

  • Microsoft has released a Windows security patch MS17-010 for Windows machines. This needs to be applied immediately and urgently.
  • Remove Windows NT4, Windows 2000 and Windows XP-2003 from production environments.
  • Block ports 139, 445 and 3389 in firewall.
  • Avoid clicking on links or opening attachments or emails from people you do not know or from companies you do not do business with.
  • SMB is enabled by default on Windows. Disable SMB service on the machine by going to Windows Features > Turn Windows Feature on and off. Uncheck the SMB feature and click OK.
  • Make sure your Windows OS software is up-to-date.
  • Have a pop-up blocker running on your web browser.
  • Regularly backup your files.
  • Install a good antivirus and a good anti-ransomware product for better security.

What are we doing on our Windows shared servers?

If you are our customer at or at and are using one of our Shared Windows Hosting plans, you do not have to worry at all. We are already in the phase of applying Windows updates on all our shared hosting Windows servers.

What you need to do in case of our Windows Dedicated Servers?

You need to patch the Windows dedicated server immediately using the steps mentioned in the link -

In-addition to this, please block the IP addresses for specified ports, domains and file names mentioned below:

IP Addresses & Ports,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Domains you should block

File Names you should block
 Please Read Me!.txt (Older variant)
 [0-9]{15}.bat #regex

You can also refer to the following links to apply the necessary fix:


For dedicated servers, once you have applied necessary changes, you need to reboot the server.

Hope the above will help you protect yourself from WannaCry Ransomware.

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About the Author
Rajeev Kumar
CEO, Computer Solutions
Jamshedpur, India

Rajeev Kumar is the primary author of How2Lab. He is a B.Tech. from IIT Kanpur with several years of experience in IT education and Software development. He has taught a wide spectrum of people including fresh young talents, students of premier engineering colleges & management institutes, and IT professionals.

Rajeev has founded Computer Solutions & Web Services Worldwide. He has hands-on experience of building variety of websites and business applications, that include - SaaS based erp & e-commerce systems, and cloud deployed operations management software for health-care, manufacturing and other industries.

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