Avast sandbox escape via unpreserved COM pathway through Task Scheduler

Overview

Improper isolation in the Avast sandbox on Windows allows a local, low-privileged attacker executing inside the sandbox to access COM interfaces to the Task Scheduler service, escape containment, and execute code with elevated privileges outside the sandbox.

The sandbox virtualizes file system and registry access but does not adequately restrict COM interface access to Task Scheduler. A process inside the sandbox can instantiate COM objects bound to Task Scheduler functionality and invoke methods to schedule and execute tasks on the host system. The Task Scheduler COM pathway is not blocked by the sandbox policy, allowing arbitrary code execution in the host security context.

This escape vector bypasses the sandbox's intended process and file isolation boundaries and can be chained with other host-level privilege escalation techniques.

Affected

• avast_antivirus_avast_one_avast_premium_security_avast_ultimate < 26.7
• avg_antivirus_free_avg_internet_security_avg_ultimate < 26.7
• norton_antivirus_plus_norton_360_standard_norton_360_deluxe_norton_360_advanced < 26.7

Remediation

Gen Digital has released a fix in Avast, AVG, and Norton version 26.7 and later. The fix restricts COM interface access to Task Scheduler from within the sandbox by adding sandbox policy rules that block the COM pathway.

Upgrade to version 26.7 or later to remediate this issue.