App Control: CDC Connectivity Error "The Client and Server Cannot Communicate Because They Do Not Possess a Common Algorithm"

Products

• Carbon Black App Control (formerly Cb Protection)

Issue/Introduction

Error in console

• "Collective Defense Cloud / Bit9 Software Reputation Service Unavailable"

Error in C:\Program Files (x86)\Bit9\Parity Server\Reporter\ParityReporter.txt

• "An unexpected error occurred on a receive. ---> System.ComponentModel.Win32Exception: The client and server cannot communicate, because they do not possess a common algorithm"

Environment

• App Control Server: 7.x - 8.x
• Microsoft Windows Server: All Supported Versions
• TLS 1.0 disabled

Cause

.Net not using the latest TLS version

Resolution

1. Add DWORD entries to the registry of the App Control application server:
   • [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319] "SchUseStrongCrypto"=dword:00000001
   • [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319] "SchUseStrongCrypto"=dword:00000001
2. Restart the App Control Server

Additional Information

Adding the registry keys will force .Net to use the latest version of TLS