Advisory Details

January 18th, 2023

Microsoft Exchange TorusUpdateInitialSessionState Uncontrolled Search Path Element Local Privilege Escalation Vulnerability

ZDI-23-011
ZDI-CAN-19492

CVE ID CVE-2023-21763
CVSS SCORE 7.8, AV:L/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 local attackers to escalate privileges on affected installations of Microsoft Exchange. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.

The specific flaw exists within the TorusUpdateInitialSessionState function. The function loads a library from an unsecured location. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code 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-2023-21763
DISCLOSURE TIMELINE
  • 2022-11-11 - Vulnerability reported to vendor
  • 2023-01-18 - Coordinated public release of advisory
CREDIT Piotr Bazydlo (@chudypb) of Trend Micro Zero Day Initiative
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