Microsoft Exchange Server Remote Code Execution Vulnerability
CVE-2021-26857

7.8HIGH

Key Information:

Vendor

Microsoft
Status
Microsoft Exchange Server 2016 Cumulative Update 19
Microsoft Exchange Server 2019 Cumulative Update 8
Microsoft Exchange Server 2019
Microsoft Exchange Server 2013 Cumulative Update 22
Vendor
CVE Published:
3 March 2021

Badges

💰 Ransomware👾 Exploit Exists🟡 Public PoC🦅 CISA Reported

What is CVE-2021-26857?

Microsoft Exchange Server Remote Code Execution Vulnerability

CISA has reported CVE-2021-26857

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 CVE-2021-26857 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 2010 Service Pack 3 Unknown 14.0.0.0

Microsoft Exchange Server 2013 Cumulative Update 21 x64-based Systems 15.00.0

Microsoft Exchange Server 2013 Cumulative Update 22 x64-based Systems 15.00.0

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.

Proxylogon-exploit
Created by sirpedrotavares

References

https://portal.msrc.microsoft.com/en-US/security-guidance...
x_refsource_MISC

EPSS Score

5% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • 💰

    Used in Ransomware

  • 🦅

    CISA Reported

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.