Vulnerability identifier: #VU25227

Vulnerability risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-0692

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Exchange Server
Server applications / Mail servers

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to uspecified error in Microsoft Exchange Server. Exploitation of this vulnerability requires Exchange Web Services (EWS) to be enabled and in use in an affected environment. A remote attacker can change parameters in the Security Access Token, forward it to a Microsoft Exchange Server and impersonate an another Exchange user. 

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2013 Cumulative Update 23 15.00.1497.002, 2019 Cumulative Update 3 15.02.0464.005, 2016 Cumulative Update 14 15.01.1847.003

---

External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0692

---

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.