NCSC-TAD-2103-001
Severity Level: Critical
Vulnerability
Reference No.: NCSC-TAD-2103-001CVSS 0
Various Exchange Server Zero-Days Under Attack
- Threat Type:
- N/A
- TLP:
- CLEAR
- CVE:
- CVE-2021-26855, CVE-2021-26857, CVE-2021-27065, CVE-2021-26858
Overview
Multiple Zero-day exploits were levraged by a chinese group attacker called HAFNIUM to attack the on-premises Microsoft Exchange Servers. The vulnerabilities allow access to on-premises Microsoft Exchange Servers that leads to gain access to email accounts, however the Exchange Online is not affected.
Affected Technologies
- on-premises Microsoft Exchange Servers
Mitigation and Immediate Actions
- 01
While the detections and IOCs help in detecting the current attacks that Microsoft has observed, it remains quite significant to apply the recently released updates for CVE-2021-26855, CVE-2021-26857, CVE-2021-27065 and CVE-2021-26858.