ASA-2019-00593 – Avast Antivirus and AVG Antivirus: DLL Preloading

A DLL Preloading vulnerability allows an attacker to implant %WINDIR%\system32\wbemcomn.dll, which is loaded into a protected-light process (PPL) and might bypass some of the self-defense mechanisms. The vulnerability gives attackers the ability to load and execute malicious payloads using multiple signed services, within the context of AVG / Avast signed processes. This ability might be abused by an attacker for different purposes such as execution and evasion, for example: Application Whitelisting Bypass.