Microsoft Exchange Server Remote Code Execution Vulnerability

CVE-2021-42321

8.8HIGH

Key Information

Vendor: Microsoft
Status: Microsoft Exchange Server 2016 Cumulative Update 21; Microsoft Exchange Server 2019 Cumulative Update 10; Microsoft Exchange Server 2016 Cumulative Update 22; Microsoft Exchange Server 2019 Cumulative Update 11
Vendor: CVE Published:; 10 November 2021

Badges

👾 Exploit Exists🔴 Public PoC🟣 EPSS 96%

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 CVE-2021-42321 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 2016 Cumulative Update 21 < 15.01.2308.020

Microsoft Exchange Server 2019 Cumulative Update 10 < 15.02.0792.019

Microsoft Exchange Server 2016 Cumulative Update 22 < 15.01.2375.017

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.

CVE-2021-42321
Created by DarkSprings

exch_CVE-2021-42321
Created by 7BitsTeam

exchange_tools
Created by gmeier909