#VU53083 Code Injection in Microsoft Exchange Server - CVE-2021-31195

Vulnerability identifier: #VU53083

Vulnerability risk: High

CVSSv4.0: 7.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]

CVE-ID: CVE-2021-31195

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Microsoft Exchange Server
Server applications / Mail servers

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to improper input validation in Microsoft Exchange Server. A remote attacker can execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2013 Cumulative Update 23 15.00.1497.002, 2016 Cumulative Update 19 15.01.2176.002 - 2016 Cumulative Update 20 15.01.2242.004, 2019 Cumulative Update 8 15.02.0792.003 - 2019 Cumulative Update 9 15.02.0858.005

---

External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31195

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.