Microsoft Exchange Validation Key Remote Code Execution Vulnerability [CVE-2020-0688]

CVE number – CVE-2020-0688

In a blog post this week, cyber security firm Rapid7 revealed that over 350,000 Microsoft Exchange servers exposed on the internet haven’t been patched against the CVE-2020-0688 post-auth remote code execution vulnerability. This comes despite Microsoft issuing a patch for the vulnerability on February 22nd.

With 350,000 Exchange servers accounting for over 80% of those exposed on the internet, admins are being urged to ensure that their servers are patched. This should entail verifying the update’s deployment on any server with the Exchange Control Panel (ECP) enabled and checking for any signs of compromise.


A remote code execution vulnerability exists in Microsoft Exchange Server when the server fails to properly create unique keys at install time.

Knowledge of a the validation key allows an authenticated user with a mailbox to pass arbitrary objects to be deserialized by the web application, which runs as SYSTEM.

The security update addresses the vulnerability by correcting how Microsoft Exchange creates the keys during install.

Patch –

Duncan Newell

Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.

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