Linux Kernel ksmbd Session Deadlock Denial-of-Service Vulnerability

May 17th, 2023
ZDI-23-701 ZDI-CAN-20591

CVE ID

CVE-2023-32253

CVSS Score

5.9 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors

Linux

Affected Products

Kernel

Vulnerability Details

This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of Linux Kernel. Authentication is not required to exploit this vulnerability, but only systems with ksmbd enabled are vulnerable.

The specific flaw exists within the processing of SMB2_SESSION_SETUP commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.

Additional Details

Linux has issued an update to correct this vulnerability. More details can be found at:
https://github.com/torvalds/linux/commit/7b4323373d844954bb76e0e9f39c4e5fc785fa7b

Disclosure Timeline

  • 2023-04-27 - Vulnerability reported to vendor
  • 2023-05-17 - Coordinated public release of advisory

Credit

Quentin Minster (@thalium_team)

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