Advisory Details

August 3rd, 2021

(Pwn2Own) Parallels Desktop Toolgate Uncontrolled Memory Allocation Privilege Escalation Vulnerability

ZDI-21-937
ZDI-CAN-13544

CVE ID CVE-2021-34854
CVSS SCORE 7.8, (AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H)
AFFECTED VENDORS Parallels
AFFECTED PRODUCTS Desktop
VULNERABILITY DETAILS

This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Desktop. An attacker must first obtain the ability to execute low-privileged code on the target guest system in order to exploit this vulnerability.

The specific flaw exists within the Toolgate component. The issue results from the lack of proper validation of user-supplied data, which can result in an uncontrolled memory allocation. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of the hypervisor.

ADDITIONAL DETAILS Parallels has issued an update to correct this vulnerability. More details can be found at:
https://kb.parallels.com/125013
DISCLOSURE TIMELINE
  • 2021-07-30 - Vulnerability reported to vendor
  • 2021-08-03 - Coordinated public release of advisory
CREDIT Billy Jheng Bing-Jhong (@st424204), Calvin Fong (@__lord_idiot) & Muhammad Alifa Ramdhan (@n0psledbyte) of STAR Labs
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