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What you need to know about the wannacry ransomware

A virulent new strain of ransomware known as WannaCry (RANSOM.WANNACRY) has hit hundreds of thousands of computers worldwide since its emergence on Friday, May 12. WannaCry is far more dangerous than other common ransomware types because of its ability to spread itself across an organization’s network by exploiting a critical vulnerability in Windows computers, which was patched by Microsoft in March 2017 (MS17-010). The exploit, known as “Eternal Blue” was released online in April in the latest of a SERIES OF LEAKS BY A GROUP KNOWN AS THE SHADOW BROKERS, who claimed that it had stolen the data from the Equation cyber espionage group.

Am I protected from the wannacry ransomware?
Symantec Endpoint Protection (SEP) have proactively blocked any attempt to exploit the vulnerability used by WannaCry, meaning customers using our Cloudbox and Symantec endpoint solutions were fully protected before WannaCry first appeared. In addition customers using our Networkbox solution were given further protection as we were able to update all devices with the required Microsoft security patches.

What is the WannaCry ransomware?
WannaCry searches for and encrypts 176 different file types and appends .WCRY to the end of the file name. It ask users to pay a US$300 ransom in bitcoins. The ransom note indicates that the payment amount will be doubled after three days. If payment is not made after seven days, the encrypted files will be deleted.

Can I recover the encrypted files or should I pay the ransom?
Decryption of encrypted files is not possible at present. If you have backup copies of affected files, you may be able to restore them. Symantec does not recommend paying the ransom.

In some cases, files may be recovered without backups. Files saved on the Desktop, My Documents, or on a removable drive are encrypted and their original copies are wiped. These are not recoverable. Files stored elsewhere on a computer are encrypted and their original copies are simply deleted. This means they could be recovered using an undelete tool.

When did WannaCry appear and how quickly did it spread?
WannaCry first appeared on Friday May 12. Symantec saw a dramatic upsurge in the number of attempts to exploit the Windows vulnerability used by WannaCry from approximately 8:00 GMT onwards. The number of exploit attempts blocked by Symantec dropped slightly on Saturday and Sunday but remained quite high.

Figure 1 Number of exploit attempts blocked by Symantec of Windows vulnerability used by WannaCry per hour
Figure 2 Number of exploit attempts blocked by Symantec of Windows vulnerability used by WannaCry per day
Figure 3. Heatmap showing Symantec detections for WannaCry, May 11 to May 15

Who is impacted?
Any unpatched Windows computer is potentially susceptible to WannaCry. Organizations are particularly at risk because of its ability to spread across networks and a number of organizations globally have been affected, the majority of which are in Europe. However individuals can also be infected

Is this a targeted attack?
No, this is not believed to be a targeted attack at this time. Ransomware campaigns are typically indiscriminate.

Why is it causing so many problems for organizations?
WannaCry has the ability to spread itself within corporate networks without user interaction, by exploiting a known vulnerability in Microsoft Windows. Computers that do not have the latest Windows security updates applied are at risk of infection.

How is WannaCry spread?
While WannaCry can spread itself across an organization’s networks by exploiting a vulnerability, the initial means of infection – how the first computer in an organization is infected remains unconfirmed. Symantec has seen some cases of WannaCry being hosted on malicious websites, but these appear to be copycat attacks, unrelated to the original attacks.

Have many people paid the ransom?
Analysis of the three Bitcoin addresses provided by the attackers for ransom payment indicate that at the time of writing, a total of 31.21 bitcoin ($53,845) had been paid in 207 separate transactions.

What are the best practices for protecting against ransomware?

  • New ransomware variants appear on a regular basis. Always keep your security software up to date to protect yourself against them.
  • Keep your operating system and other software updated. Software updates will frequently include patches for newly discovered security vulnerabilities that could be exploited by ransomware attackers.
  • Email is one of the main infection methods. Be wary of unexpected emails especially if they contain links and/or attachments.
  • Be extremely wary of any Microsoft Office email attachment that advises you to enable macros to view its content. Unless you are absolutely sure that this is a genuine email from a trusted source, do not enable macros and instead immediately delete the email.
  • Backing up important data is the single most effective way of combating ransomware infection. Attackers have leverage over their victims by encrypting valuable files and leaving them inaccessible. If the victim has backup copies, they can restore their files once the infection has been cleaned up. However organizations should ensure that back-ups are appropriately protected or stored off-line so that attackers can’t delete them.
  • Using cloud services could help mitigate ransomware infection, since many retain previous versions of files, allowing you to roll back to the unencrypted form.

Please contact us should you have any queries or require any advice.

Regards
Justin Trent
CEOvv

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