#VU47598 Information disclosure in Microsoft Exchange Server - CVE-2020-16969

Vulnerability identifier: #VU47598

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

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

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External links
https://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.