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Exploited in the wildUsed by ransomwareServers & business softwareWork IT

CVE-2018-8581 Microsoft Exchange Server: privilege escalation

In plain words: Something running with limited rights can promote itself to full control. Turns a small foothold (like a malicious app) into administrator or system-level access.

Confirmed exploited by CISA on · US federal patch deadline Mar 17, 2022

What to do

  1. Install Microsoft's security update for Exchange Server. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Keep a list of every internet-facing server you run so nothing is forgotten.
  3. Patch anything in this catalog first, ahead of normal patch cycles.
  4. Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.

The details

Official name
Microsoft Exchange Server Privilege Escalation Vulnerability
Product
Microsoft Exchange Server
CISA description
A privilege escalation vulnerability exists in Microsoft Exchange Server. An attacker who successfully exploited this vulnerability could attempt to impersonate any other user of the Exchange server.
Type of flaw
Privilege escalation
Confirmed exploited
Mar 3, 2022 — known to be used in ransomware attacks
US federal patch deadline
Mar 17, 2022

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Answering about CVE-2018-8581 ·

Questions about CVE-2018-8581

Is CVE-2018-8581 being exploited?

Yes. CISA added CVE-2018-8581 to its Known Exploited Vulnerabilities catalog on Mar 3, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.

How do I fix CVE-2018-8581?

Install Microsoft's security update for Exchange Server. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.

Am I affected by CVE-2018-8581?

Only if you use Microsoft Exchange Server. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

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