Security Updates for Exchange (July 2021)

high Nessus Plugin ID 151664
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 Microsoft Exchange Server installed on the remote host is affected by multiple vulnerabilities.


The Microsoft Exchange Server installed on the remote host is missing security updates. It is, therefore, affected by multiple vulnerabilities:

- A remote code execution vulnerability. An attacker can exploit this to bypass authentication and execute unauthorized arbitrary commands. (CVE-2021-31196, CVE-2021-31206)

- An elevation of privilege vulnerability. An attacker can exploit this to gain elevated privileges. (CVE-2021-33768, CVE-2021-34470)

Note: Nessus is unable to determine if the latest Active Directory schema has been applied.


Microsoft has released the following KBs to address these issues:
- KB5003611
- KB5003612
- KB5004778
- KB5004779
- KB5004780

See Also

Plugin Details

Severity: High

ID: 151664

File Name: smb_nt_ms21_jul_exchange.nasl

Version: 1.7

Type: local

Agent: windows

Published: 7/15/2021

Updated: 10/14/2021

Dependencies: ms_bulletin_checks_possible.nasl, microsoft_exchange_installed.nbin

Risk Information

CVSS Score Source: CVE-2021-31206


Risk Factor: Critical

Score: 9


Risk Factor: High

Base Score: 7.9

Temporal Score: 6.9

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

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


Risk Factor: High

Base Score: 8

Temporal Score: 7.6

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

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

Vulnerability Information

CPE: cpe:/a:microsoft:exchange_server

Required KB Items: SMB/MS_Bulletin_Checks/Possible

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/13/2021

Vulnerability Publication Date: 7/13/2021

Reference Information

CVE: CVE-2021-31196, CVE-2021-31206, CVE-2021-33768, CVE-2021-34470

MSKB: 5003611, 5003612, 5004778, 5004779, 5004780

MSFT: MS21-5003611, MS21-5003612, MS21-5004778, MS21-5004779, MS21-5004780

IAVA: 2021-A-0315-S