Advisory Details

This vulnerability allows local attackers to escalate privileges on affected installations of Avast Cleanup Premium. 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 Avast Cleanup Service. By creating a symbolic link, an attacker can abuse the service to delete a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM.

02/28/24 – ZDI reported the vulnerability to Avast’s Security Reports team.
09/27/23 – ZDI asked for updates.
06/19/24 –ZDI asked for updates.
07/26/24 - ZDI informed the vendor that since we have not received a response, we will publish the case as a zero-day advisory on 07/29/24

-- Mitigation: Given the nature of the vulnerability, the only salient mitigation strategy is to restrict interaction with the application.

• 2024-02-28 - Vulnerability reported to vendor
• 2024-07-29 - Coordinated public release of advisory
• 2024-08-15 - Advisory Updated