What is Ransomware?

Ransomware is a malicious software that encrypts the files and locks device, such as
a computer, tablet or smartphone and then demands a ransom to unlock it. Recently, a
dangerous ransomware named 'Wannacry' has been affecting the computers worldwide
creating the biggest ransomware attack the world has ever seen. This has affected
computers in India also.

What is WannaCry Ransomware?

WannaCry ransomware attacks windows based machines. It also goes by the name
WannaCrypt, WannaCry, WanaCrypt0r, WCrypt, WCRY.It leverages SMB exploit in
Windows machines called EternalBlue to attack and inject the malware. All versions of
windows before Windows 10 are vulneable to this attack if not patched for MS-17-010.
After a system is affected, it encrypts the files and shows a pop up with a countdown and
instructions on how to pay the 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 600$ and threatens the
user to wipe off all the data. It also installs DOUBLEPULSAR backdoor in the machine.

How it spreads?

It 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 spreding itself in a network by means of a vulneability in Windows SMB. It
scans the network for specific ports, searches for the vulneability and then exploits it to
inject the malware in the new machine and thus it spreads widely across the network.

These OSes are affected

The attack exploits a vulnerability in older Windows operating systems, namely:

Windows 8
Windows XP
Windows Server 2003

If you're using a more recent version of Windows -- and you've stayed up up-to-date on your system updates -- you should not be vulnerable to the current iteration of the WannaCry ransomware:

Windows 10
Windows 8.1
Windows 7
Windows Vista
Windows Server 2008
Windows Server 2008 R2
Windows Server 2012
Windows Server 2012 R2
Windows Server 2016

What can you do to prevent infection?

→ Microsoft has released a Windows security patch MS17-010 for Winodws machines.
This needs to be applied immediately and urgently. Download And Install Patch From Here

→ Remove Windows NT4, Windows 2000 and Windows XP-2003 from production

→ Block ports 139, 445 and 3389 in firewall.

→ Avoid clicking on links or opening attachments or emails from people you don't
know or companies you don't do business with.

→ SMB is enabled by default on Windows. Disable smb service on the machine by
going to Settings > uncheck the settings > OK

  Click Here To Find How To Disable SMB

→ Make sure your 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 antiransomware product for better security

→ Below is a consolidated list that we need to block on you firewall/antivirus

IPs To Blocks

Domains To Block:

• iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea[.]com
• Rphjmrpwmfv6v2e[dot]onion
• Gx7ekbenv2riucmf[dot]onion
• 57g7spgrzlojinas[dot]onion
• xxlvbrloxvriy2c5[dot]onion
• 76jdd2ir2embyv47[dot]onion
• cwwnhwhlz52maqm7[dot]onion
File Names:
• @Please_Read_Me@.txt
• @WanaDecryptor@.exe
• @WanaDecryptor@.exe.lnk
• Please Read Me!.txt (Older variant)
• C:\WINDOWS\tasksche.exe
• C:\WINDOWS\qeriuwjhrf
• 131181494299235.bat
• 176641494574290.bat
• 217201494590800.bat
• [0-9]{15}.bat #regex
• !WannaDecryptor!.exe.lnk
• 00000000.pky
• 00000000.eky
• 00000000.res
• C:\WINDOWS\system32\taskdl.exe

Source: cnet, microsoft

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