CVE-2021-31198: (Pwn2Own) Microsoft Exchange Server OAB Arbitrary File Write Remote Code Execution Vulnerability

Published May 11, 2021
·
Updated

Microsoft Exchange Server Remote Code Execution Vulnerability

Other sources

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft Exchange Server. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the OAB service. The issue results from the lack of proper validation of user-supplied data, which can allow arbitrary files write to OAB folders. An attacker can leverage this vulnerability to execute arbitrary code in the context of SYSTEM.

Affected Software

6 affected components
Microsoft Exchange
Microsoft Exchange Server=2013-cumulative_update_23
Microsoft Exchange Server=2016-cumulative_update_19
Microsoft Exchange Server=2016-cumulative_update_20
Microsoft Exchange Server=2019-cumulative_update_8
Microsoft Exchange Server=2019-cumulative_update_9

Event History

May 11, 2021
CVE Published
via MITRE·07:11 PM
Data Sourced
via MITRE·07:11 PM
DescriptionSeverity
Data Sourced
via NVD·07:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Aug 3, 2024
Advisory Published
via ZDI·11:00 PM

Frequently Asked Questions

1

What is CVE-2021-31198?

CVE-2021-31198 is a vulnerability in Microsoft Exchange Server that allows remote attackers to execute arbitrary code on affected installations.

2

What is the severity of CVE-2021-31198?

CVE-2021-31198 has a severity rating of 8.8 (high).

3

Which versions of Microsoft Exchange Server are affected by CVE-2021-31198?

CVE-2021-31198 affects Microsoft Exchange Server 2013 Cumulative Update 23, 2016 Cumulative Update 19 and 20, and 2019 Cumulative Update 8 and 9.

4

How can CVE-2021-31198 be exploited?

CVE-2021-31198 can be exploited by bypassing the existing authentication mechanism and exploiting the flaw in the OAB service.

5

Where can I find more information about CVE-2021-31198?

You can find more information about CVE-2021-31198 on the Microsoft Security Response Center (MSRC) website and the Zero Day Initiative (ZDI) website.

Contact

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