CVE-2021-42287
Microsoft Active Directory Domain Services Privilege Escalation Vulnerability
Microsoft Active Directory
Active Directory Domain Services Elevation of Privilege Vulnerability
Ransomware groups exploiting CVE-2021-42287
"Black Basta" is a new ransomware strain discovered during April 2022 - looks in dev since at least early February 2022 - and due to their ability to quickly amass new victims and the style of their negotiations, this is likely not a new operation but rather a
Exploitation is attributed to these groups across their recorded activity. It does not follow that every organisation they listed was reached through CVE-2021-42287 — the source data does not record an entry point per incident.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 11 April 2022. US federal agencies were required to remediate it by 2 May 2022. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 77.2%, which is higher than 99.5% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Recent listings by these groups
Disclosures from the groups above, newest first.
Frequently asked questions
Is CVE-2021-42287 being exploited by ransomware groups?
Yes. CVE-2021-42287 is recorded as exploited by Blackbasta. Between them these groups account for 193 victim disclosures in this database. CISA also records this vulnerability as used in ransomware campaigns.
What does CVE-2021-42287 affect?
CVE-2021-42287 affects Microsoft Active Directory. Active Directory Domain Services Elevation of Privilege Vulnerability
How severe is CVE-2021-42287?
CVE-2021-42287 is rated HIGH with a CVSS base score of 7.5. EPSS puts the probability of exploitation in the next 30 days at 77.2%, higher than 99.5% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 2 May 2022.
How should organisations respond to CVE-2021-42287?
Apply the vendor patch for Microsoft Active Directory as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.