Vulnerability identifier: #VU86404

Vulnerability risk: Critical

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2024-21410

CWE-ID: CWE-668

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 compromise the affected system.

The vulnerability exists due to an error in Microsoft Exchange Server. A remote attacker can target an NTLM client such as Outlook with an NTLM credentials-leaking type vulnerability. The leaked credentials can then be relayed against the Exchange server to gain privileges as the victim client and to perform operations on the Exchange server on the victim's behalf.

Note, the vulnerability is being actively exploited in the wild.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2016 CU23 Nov23SU 15.01.2507.035, 2019 Cumulative Update 1 15.02.0330.005 - 2019 RTM 15.02.0221.012

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External links
http://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2024-21410

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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?

Yes. This vulnerability is being exploited in the wild.