Microsoft Exchange Server Remote Code Execution Vulnerability
CVE-2021-34473

9.1CRITICAL

Key Information:

Badges

💰 Ransomware👾 Exploit Exists🟡 Public PoC🟣 EPSS 96%🦅 CISA Reported

Summary

Microsoft Exchange Server Remote Code Execution Vulnerability

CISA Reported

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed as being exploited and is known by the CISA as enabling ransomware campaigns.

The CISA's recommendation is: Apply updates per vendor instructions.

Affected Version(s)

Microsoft Exchange Server 2013 Cumulative Update 23 x64-based Systems 15.00.0 < 15.00.1497.015

Microsoft Exchange Server 2016 Cumulative Update 19 x64-based Systems 15.01.0 < 15.01.2176.012

Microsoft Exchange Server 2016 Cumulative Update 20 x64-based Systems 15.01.0 < 15.01.2242.008

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

References

EPSS Score

96% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 💰

    Used in Ransomware

  • 👾

    Exploit known to exist

  • 🦅

    CISA Reported

  • Vulnerability published

  • Vulnerability Reserved

Collectors

NVD DatabaseMitre DatabaseCISA Database8 Proof of Concept(s)
.