This indicates an attack attempt against a Remote Code Execution vulnerability in the Avast Antivirus.
The vulnerability is caused by an error when the vulnerable software handle a malformed TLS packet. A remote attacker can exploit this to execute arbitrary code in the context of the affected application via a crafted request.
AVAST Software Antivirus
System Compromise: Remote attackers can gain control of vulnerable systems
Currently we are unaware of any vendor supplied patch for this issue.