This security advisory describes one medium risk vulnerability.
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] [PCI]
CWE-200 - Information Exposure
Exploit availability: NoDescription
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, 2016 Cumulative Update 17, 2019 Cumulative Update 6CPE
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.