CVE-2021-42278 Microsoft Active Directory: 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 May 2, 2022
What to do
- Install Microsoft's security update for Active Directory. 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.
- Patch anything in this catalog first, ahead of normal patch cycles.
- 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 Active Directory Domain Services Privilege Escalation Vulnerability
- Product
- Microsoft Active Directory
- CISA description
- Microsoft Active Directory Domain Services contains an unspecified vulnerability that allows for privilege escalation.
- Type of flaw
- Privilege escalation (CWE-20)
- Confirmed exploited
- Apr 11, 2022 — known to be used in ransomware attacks
- US federal patch deadline
- May 2, 2022
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Answering about CVE-2021-42278 ·
Questions about CVE-2021-42278
Is CVE-2021-42278 being exploited?
Yes. CISA added CVE-2021-42278 to its Known Exploited Vulnerabilities catalog on Apr 11, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-42278?
Install Microsoft's security update for Active Directory. 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-2021-42278?
Only if you use Microsoft Active Directory. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.