Microsoft Exchange Server RCE (ProxyShell)

critical Nessus Plugin ID 152458
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.


The remote mail server is affected by a remote code execution vulnerability.


The Microsoft Exchange running on the remote host is affected by a remote code execution vulnerability. An unauthenticated remote attacker can exploit this to execute arbitrary code.


Microsoft has released the following security updates to address this issue:

See Also

Plugin Details

Severity: Critical

ID: 152458

File Name: exchange_proxyshell.nbin

Version: 1.6

Type: remote

Agent: windows

Family: Windows

Published: 8/11/2021

Updated: 10/19/2021

Dependencies: owa-version.nasl

Risk Information

CVSS Score Source: CVE-2021-34473


Risk Factor: Critical

Score: 9.8


Risk Factor: Critical

Base Score: 10

Temporal Score: 8.3

Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C

Temporal Vector: E:F/RL:OF/RC:C


Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:F/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:microsoft:exchange_server

Required KB Items: installed_sw/Outlook Web Access

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/13/2021

Vulnerability Publication Date: 7/13/2021

Exploitable With

Metasploit (Microsoft Exchange ProxyShell RCE)

Reference Information

CVE: CVE-2021-34473

MSKB: 5001799

MSFT: MS21-5001799