Unfortunately attack surface on AV also includes Windows Defender itself:
https://arstechnica.com/information-technology/2017/06/lates...
This is why security mono-culture is dangerous and it's in our interest to maintain a diverse ecosystem of security vendors in every area. Security is hard and anyone can have a serious vulnerability.
Re:Malware identified in CCleaner 5.33
by Dylan16807 on Monday September 18, 2017 @01:10PM
(#15277632)
I'll still take 1-2 vendors that actually have security as a top priority over a variety of vendors that care plenty about features and detection rates but not about actually hardening their code.
Surprise, surprise, now there is more attack surface available since AV is kernel level. And so now we see attacks getting root or kernel level access via AV vulnerabilities.