Zero-day vulnerability in Microsoft Exchange Server

Exposure of Resource to Wrong Sphere
CVE-2024-21410

Vulnerability details

Advisory: SB2024021336 - Privilege escalation in Microsoft Exchange Server

Vulnerable component: Microsoft Exchange Server

CVE-ID: CVE-2024-21410

CVSSv3 score: 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

CWE-ID: CWE-668 - Exposure of resource to wrong sphere

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.

External links:

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

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.