Security News > 2023 > December > Over 20,000 vulnerable Microsoft Exchange servers exposed to attacks
Tens of thousands of Microsoft Exchange email servers in Europe, the U.S., and Asia exposed on the public internet are vulnerable to remote code execution flaws.
Internet scans from The ShadowServer Foundation show that there are close to 20,000 Microsoft Exchange servers currently reachable over the public internet that have reached the end-of-life stage.
ShadowServer's statistics may not show the complete picture as Macnica security researcher Yutaka Sejiyama discovered a little over 30,000 Microsoft Exchange servers that reached end of support.
Some of the machines running older versions of the Exchange mail server are vulnerable to ProxyLogon, a critical security issue tracked as CVE-2021-26855, that can be chained with a less severe bug identified as CVE-2021-27065 to achieve remote code execution.
Even if companies still running outdated Exchange servers have implemented available mitigations, the measure is not sufficient as Microsoft recommends prioritizing the installation of updates on the servers that are externally facing.
New Microsoft Exchange zero-days allow RCE, data theft attacks.
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Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2021-03-03 | CVE-2021-26855 | Server-Side Request Forgery (SSRF) vulnerability in Microsoft Exchange Server 2013/2016/2019 Microsoft Exchange Server Remote Code Execution Vulnerability | 9.1 |
| 2021-03-03 | CVE-2021-27065 | Path Traversal vulnerability in Microsoft Exchange Server 2013/2016/2019 Microsoft Exchange Server Remote Code Execution Vulnerability | 7.8 |