Does Disabling the CRL Check on Sensors Open Communications to Man in the Middle Attacks?

Products

• Carbon Black Cloud Endpoint Standard (formerly Cb Defense)
• Carbon Black Cloud Enterprise EDR (formerly Cb Threathunter)

Issue/Introduction

Does disabling the Certificate Revocation List (CRL) check at the time of Sensor install result in the Sensor becoming open to man-in-the-middle attacks?

Environment

• Carbon Black Cloud Sensor: All Supported Versions 
• Microsoft Windows: All supported versions

Resolution

Disabling the CRL check does not immediately open the Sensor to man in the middle attacks

• Disabling of the CRL check could be leveraged for a man in the middle attack if a Sensor/Backend communication certificate is revoked
• Additional information can be found about What are some concerns with disabling the CRL check within the Sensor?

Additional Information

• CRL checks often fail when proxies are involved because the CRL check process is offloaded to WinHTTP
• Sensor can also be configured to make a best effort CRL check