Vulnerability identifier: #VU79146

Vulnerability risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-21709

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 application does not properly impose security restrictions in Microsoft Exchange Server. A remote attacker can perform a brute-force attack, which leads to security restrictions bypass and privilege escalation.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2019 Preview 15.02.0196.000 - 2019 CU13 Jun23SU 15.02.1258.016, 2016 Preview 15.01.0225.016 - 2016 CU23 Jun23SU 15.01.2507.027

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2023-21709

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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.