Vulnerability identifier: #VU47598

Vulnerability risk: Medium

CVSSv3.1: 6.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-16969

CWE-ID: CWE-200

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 gain access to potentially sensitive information.

The vulnerability exists due to the Microsoft Exchange improperly validates tokens when handling certain messages. A remote attacker can send specially crafted OWA messages and gain unauthorized access to sensitive information on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2019 Cumulative Update 6 15.02.0659.004, 2016 Cumulative Update 17 15.01.2044.004, 2013 Cumulative Update 23 15.00.1497.002

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16969

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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.