(Pwn2Own) Linux Kernel io_uring Improper Update of Reference Count Privilege Escalation Vulnerability

October 21st, 2022
ZDI-22-1462 ZDI-CAN-17428

CVE ID

CVE-2022-2602

CVSS Score

8.8 AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected Vendors

Linux

Affected Products

Kernel

Vulnerability Details

This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. 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 io_uring API. The issue results from the improper management of a reference count. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root.

Additional Details

Linux has issued an update to correct this vulnerability. More details can be found at:
https://ubuntu.com/security/CVE-2022-2602

Disclosure Timeline

  • 2022-05-25 - Vulnerability reported to vendor
  • 2022-10-21 - Coordinated public release of advisory

Credit

Billy Jheng Bing-Jhong (https://twitter.com/st424204) of STAR Labs

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