• An Analysis of the WannaCry Ransomware Outbreak
• KB91863 - Threat Advisory: Ransom-WannaCry 
• How to Protect Against Ransomware 

• Endpoint Security (ENS) 2978 or higher *
• VirusScan Enterprise (VSE) 8527 or higher * 

* McAfee-defined content protection against known variants.  

As a best practice, configure repository update tasks with a minimal refresh interval. This practice makes sure that new content is applied when we release it.

This article is updated as and when additional information is available. Continue to monitor this article for updates.

Topics in this article

Symptoms of infected systems
VSE Access Protection rules
ENS Access Protection rules
ENS Adaptive Threat Protection – Real Protect and Dynamic Application Containment
ENS Dynamic Application Containment rules
Advanced Threat Defense coverage for WannaCry Ransomware
NSP coverage for WannaCry Ransomware
Frequently Asked Questions  

This threat exhibits the following symptoms on infected systems:

• Files are encrypted with the .wnry, .wcry, .wncry, .wcryt, and .wncryt extension. Users see a screen with a ransom message.
• Users see the following Ransom-WannaCry Desktop Background:
   
• On restarting, impacted systems have a blue screen error and can't start. 
• Encryption is seen on the local host and open SMB shares.
  
  IMPORTANT: Immediately install the Critical Microsoft Patch MS17-010 to prevent SMB shares from becoming encrypted. For details, see this Microsoft article.

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ENS and VSE Access Protection Proactive Measures

Use VSE Access Protection rules:

Rule 1:

Rule Type: Registry Blocking Rule
Process to include: *
Registry key or value to protect: HKLM - /Software/WanaCrypt0r
Registry key or value p protect: Key
File actions to prevent: Create key or value

Rule 2:

Rule Type: File/Folder Blocking Rule
Process to include: *
File or folder name to block: *.wnry
File actions to prevent: New files being created

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Use ENS Access Protection rules:

Rule 1:

Executable 1:

Inclusion: Include
File Name or Path: *

SubRule 1:

SubRule Type: Registry key
Operations: Create
Target 1:

Inclusion: Include
File, folder name, or file path: *\Software\WanaCrypt0r

SubRule 2:

SubRule Type: Files
Operations: Create
Target 1:

Inclusion: Include
File, folder name, or file path: *.wnry

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ENS with Adaptive Threat Protection (ATP) – Real Protect and Dynamic Application Containment (DAC) 

ENS ATP Real Protect, with DAC, provides next-generation protection against unknown exploits.

ENS ATP provides full protection against all known variants of the WannaCry exploit. We recommend the following ATP configuration for detection of unknown WannaCry variants.

1. Configure the following setting in the Adaptive Threat Protection - Options Policy:

Rule Assignment = Security (default setting is Balanced)

2. Configure the following rules in the Adaptive Threat Protection – Dynamic Application Containment policy:

Dynamic Application Containment – Containment Rules

See KB87843 - Dynamic Application Containment rules and best practices, and set the recommended DAC rules to Block as prescribed.

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ENS DAC rules triggered by Ransom-WannaCry variants

This section provides additional information about observed DAC rules triggered by known WannaCry variants. For processes that other layers of the ENS security stack don't detect, extra rule enablement might not be needed to effectively contain the processes. See KB87843 - Dynamic Application Containment rules and best practices, and set the recommended DAC rules to Block as prescribed.

Rule 1:

Rule Name: Executing any child process

Rule 2:

Rule Name: Accessing user cookie locations

Rule 3:

Rule Name: Creating files with the .html, .jpg, or .bmp extension

Rule 4:

Rule Name: Creating files with the .exe extension

Rule 5:

Rule Name: Modifying users' data folders

Rule 6:

Rule Name: Modifying startup registry locations

Rule 7:

Rule Name: Modifying critical Windows files and registry locations

Rule 8:

Rule Name: Reading or modifying files on any network location

Rule 9:

Rule Name: Modifying files with the .bat extension

Rule 10:

Rule Name: Modifying files with the .vbs extension

Rule 11:

Rule Name: Creating files with the .bat extension

Rule 12:

Rule Name: Reading files commonly targeted by ransomware-class malware

Rule 13:

Rule Name: Creating files on any network location

Rule 14:

Rule Name: Writing to files commonly targeted by ransomware-class malware

Rule 15:

Rule Name: Modifying the hidden attribute bit

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Advanced Threat Defense (ATD) Content Update Package for WannaCry available in the following builds, or later:

3.6.x – 3.6.2.103.61987 or later
3.8.x package – 3.8.2.170207.59307 or later
3.10.x – 3.10.2.170712.61985 or later
4.0 – Detection included in base install

NSP coverage for WannaCry Ransomware:

Existing signatures:

• 0x43c0b800- NETBIOS-SS: Windows SMBv1 identical MID and FID type confusion vulnerability (CVE-2017-0143)   
• 0x43c0b400- NETBIOS-SS: Windows SMB Remote Code Execution Vulnerability (CVE-2017-0144)   
• 0x43c0b500- NETBIOS-SS: Windows SMB Remote Code Execution Vulnerability (CVE-2017-0145) 
• 0x43c0b300- NETBIOS-SS: Microsoft Windows SMB Out of bound Write Vulnerability (CVE-2017-0146)
• 0x43c0b900- NETBIOS-SS: Windows SMBv1 information disclosure vulnerability (CVE-2017-0147)

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Frequently Asked Questions about Ransom-WannaCry