Advisory Details

January 18th, 2023

Microsoft Exchange PowerShell Unsafe Reflection NTLM Relay Vulnerability

CVE ID	CVE-2023-21745
CVSS SCORE	8.8, AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
AFFECTED VENDORS	Microsoft
AFFECTED PRODUCTS	Exchange
VULNERABILITY DETAILS	This vulnerability allows remote attackers to relay NTLM credentials on affected installations of Microsoft Exchange. Authentication is required to exploit this vulnerability. The specific flaw exists within the PowerShell endpoint. The process does not properly restrict a user-supplied argument before using it to create an instance of an object. An attacker can leverage this vulnerability to relay NTLM credentials in the context of SYSTEM.
ADDITIONAL DETAILS	Microsoft has issued an update to correct this vulnerability. More details can be found at: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21745
DISCLOSURE TIMELINE	2022-09-29 - Vulnerability reported to vendor 2023-01-18 - Coordinated public release of advisory 2024-10-16 - Advisory Updated
CREDIT	Piotr Bazydlo (@chudypb) of Trend Micro Zero Day Initiative

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