Advisory Details

November 15th, 2023

Microsoft Exchange IsUNCPath Improper Input Validation NTLM Relay Vulnerability

ZDI-23-1637
ZDI-CAN-21983

CVE ID CVE-2023-36035
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 IsUNCPath method. The issue results from the lack of proper input validation. 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-2023-36035
DISCLOSURE TIMELINE
  • 2023-08-25 - Vulnerability reported to vendor
  • 2023-11-15 - Coordinated public release of advisory
CREDIT Piotr Bazydlo (@chudypb) of Trend Micro Zero Day Initiative
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